Replace TString with TRope in TEvPut

replace TString with TRope in TEvPut

35 files changed, 251 insertions, 184 deletions

diff --git a/library/cpp/actors/util/rope.h b/library/cpp/actors/util/rope.h
index 54b8e344124..fd4a5acdba1 100644
--- a/library/cpp/actors/util/rope.h
+++ b/library/cpp/actors/util/rope.h
@@ -1060,7 +1060,7 @@ public:
         Erase(Begin(), End());
     }
 
-    bool IsContiguous() {
+    bool IsContiguous() const {
         if(Begin() == End() || (++Begin() == End())) {
             return true;
         }
diff --git a/ydb/core/base/blobstorage.h b/ydb/core/base/blobstorage.h
index 0748eb6f780..d8bc5b3529c 100644
--- a/ydb/core/base/blobstorage.h
+++ b/ydb/core/base/blobstorage.h
@@ -16,6 +16,8 @@
 
 #include <library/cpp/actors/wilson/wilson_trace.h>
 #include <library/cpp/lwtrace/shuttle.h>
+#include <library/cpp/actors/util/rope.h>
+#include <library/cpp/actors/util/shared_data_rope_backend.h>
 
 #include <util/stream/str.h>
 #include <util/generic/xrange.h>
@@ -903,7 +905,7 @@ struct TEvBlobStorage {
         };
 
         const TLogoBlobID Id;
-        const TString Buffer;
+        const TRope Buffer; //FIXME(innokentii) const members prevent usage of move-semantics elsewhere
         const TInstant Deadline;
         const NKikimrBlobStorage::EPutHandleClass HandleClass;
         const ETactic Tactic;
@@ -912,35 +914,49 @@ struct TEvBlobStorage {
         std::vector<std::pair<ui64, ui32>> ExtraBlockChecks; // (TabletId, Generation) pairs
         bool Decommission = false; // is it generated by decommission and should bypass all block checks?
 
-        TEvPut(const TLogoBlobID &id, const TString &buffer, TInstant deadline,
+        TEvPut(const TLogoBlobID &id, TRope &&buffer, TInstant deadline,
                NKikimrBlobStorage::EPutHandleClass handleClass = NKikimrBlobStorage::TabletLog,
                ETactic tactic = TacticDefault)
             : Id(id)
-            , Buffer(buffer)
+            , Buffer(std::move(buffer))
             , Deadline(deadline)
             , HandleClass(handleClass)
             , Tactic(tactic)
         {
             Y_VERIFY(Id, "EvPut invalid: LogoBlobId must have non-zero tablet field, id# %s", Id.ToString().c_str());
-            Y_VERIFY(buffer.size() < (40 * 1024 * 1024),
+            Y_VERIFY(Buffer.size() < (40 * 1024 * 1024),
                    "EvPut invalid: LogoBlobId# %s buffer.Size# %zu",
-                   id.ToString().data(), buffer.size());
-            Y_VERIFY(buffer.size() == id.BlobSize(),
+                   id.ToString().data(), Buffer.size());
+            Y_VERIFY(Buffer.size() == id.BlobSize(),
                    "EvPut invalid: LogoBlobId# %s buffer.Size# %zu",
-                   id.ToString().data(), buffer.size());
+                   id.ToString().data(), Buffer.size());
+            Y_VERIFY(Buffer.IsContiguous(), "EvPut invalid: buffer must be contiguous");
             REQUEST_VALGRIND_CHECK_MEM_IS_DEFINED(&id, sizeof(id));
-            REQUEST_VALGRIND_CHECK_MEM_IS_DEFINED(buffer.Data(), buffer.size());
+            REQUEST_VALGRIND_CHECK_MEM_IS_DEFINED(Buffer.GetContiguousSpan.Data(), Buffer.size());
             REQUEST_VALGRIND_CHECK_MEM_IS_DEFINED(&deadline, sizeof(deadline));
             REQUEST_VALGRIND_CHECK_MEM_IS_DEFINED(&handleClass, sizeof(handleClass));
             REQUEST_VALGRIND_CHECK_MEM_IS_DEFINED(&tactic, sizeof(tactic));
         }
 
+        TEvPut(const TLogoBlobID &id, const TString &buffer, TInstant deadline,
+               NKikimrBlobStorage::EPutHandleClass handleClass = NKikimrBlobStorage::TabletLog,
+               ETactic tactic = TacticDefault)
+            : TEvPut(id, TRope(buffer), deadline, handleClass, tactic)
+        {}
+
+
+        TEvPut(const TLogoBlobID &id, const TSharedData &buffer, TInstant deadline,
+               NKikimrBlobStorage::EPutHandleClass handleClass = NKikimrBlobStorage::TabletLog,
+               ETactic tactic = TacticDefault)
+            : TEvPut(id, TRope(MakeIntrusive<TRopeSharedDataBackend>(buffer)), deadline, handleClass, tactic)
+        {}
+
         TString Print(bool isFull) const {
             TStringStream str;
             str << "TEvPut {Id# " << Id.ToString();
-            str << " Size# " << Buffer.size();
+            str << " Size# " << Buffer.GetSize();
             if (isFull) {
-                str << " Buffer# " << Buffer.Quote();
+                str << " Buffer# " << Buffer.ConvertToString().Quote();
             }
             str << " Deadline# " << Deadline.MilliSeconds();
             str << " HandleClass# " << HandleClass;
@@ -954,7 +970,7 @@ struct TEvBlobStorage {
         }
 
         ui32 CalculateSize() const {
-            return sizeof(*this) + Buffer.capacity();
+            return sizeof(*this) + Buffer.GetSize();
         }
 
         std::unique_ptr<TEvPutResult> MakeErrorResponse(NKikimrProto::EReplyStatus status, const TString& errorReason,
diff --git a/ydb/core/blob_depot/agent/storage_put.cpp b/ydb/core/blob_depot/agent/storage_put.cpp
index 875af36a284..3c7c79cc466 100644
--- a/ydb/core/blob_depot/agent/storage_put.cpp
+++ b/ydb/core/blob_depot/agent/storage_put.cpp
@@ -77,11 +77,11 @@ namespace NKikimr::NBlobDepot {
                 footer.StoredBlobId = msg.Id;
                 TStringBuf footerData(reinterpret_cast<const char*>(&footer), sizeof(footer));
 
-                auto put = [&](EBlobType type, const TString& buffer) {
+                auto put = [&](EBlobType type, TRope&& buffer) {
                     const auto& [id, groupId] = kind.MakeBlobId(Agent, BlobSeqId, type, 0, buffer.size());
                     Y_VERIFY(!locator->HasGroupId() || locator->GetGroupId() == groupId);
                     locator->SetGroupId(groupId);
-                    auto ev = std::make_unique<TEvBlobStorage::TEvPut>(id, buffer, msg.Deadline, msg.HandleClass, msg.Tactic);
+                    auto ev = std::make_unique<TEvBlobStorage::TEvPut>(id, std::move(buffer), msg.Deadline, msg.HandleClass, msg.Tactic);
                     ev->ExtraBlockChecks = msg.ExtraBlockChecks;
                     if (!msg.Decommission) { // do not check original blob against blocks when writing decommission copy
                         ev->ExtraBlockChecks.emplace_back(msg.Id.TabletID(), msg.Id.Generation());
@@ -92,15 +92,18 @@ namespace NKikimr::NBlobDepot {
 
                 if (SuppressFooter) {
                     // write the blob as is, we don't need footer for this kind
-                    put(EBlobType::VG_DATA_BLOB, msg.Buffer);
+                    put(EBlobType::VG_DATA_BLOB, TRope(msg.Buffer));
                 } else if (msg.Buffer.size() + sizeof(TVirtualGroupBlobFooter) <= MaxBlobSize) {
                     // write single blob with footer
-                    put(EBlobType::VG_COMPOSITE_BLOB, msg.Buffer + footerData);
+                    TRope buffer = msg.Buffer;
+                    buffer.Insert(buffer.End(), TRope(TString(footerData))); //FIXME(innokentii)
+                    buffer.Compact();
+                    put(EBlobType::VG_COMPOSITE_BLOB, std::move(buffer));
                 } else {
                     // write data blob and blob with footer
-                    put(EBlobType::VG_DATA_BLOB, msg.Buffer);
-                    put(EBlobType::VG_FOOTER_BLOB, TString(footerData));
-                }
+                    put(EBlobType::VG_DATA_BLOB, TRope(msg.Buffer));
+                    put(EBlobType::VG_FOOTER_BLOB, TRope(TString(footerData)));
+               }
             }
 
             void OnUpdateBlock(bool success) override {
diff --git a/ydb/core/blobstorage/dsproxy/dsproxy_blackboard.cpp b/ydb/core/blobstorage/dsproxy/dsproxy_blackboard.cpp
index a602caf8ff6..8b7af89d97d 100644
--- a/ydb/core/blobstorage/dsproxy/dsproxy_blackboard.cpp
+++ b/ydb/core/blobstorage/dsproxy/dsproxy_blackboard.cpp
@@ -15,7 +15,7 @@ void TBlobState::TState::AddResponseData(ui32 fullSize, ui32 shift, TString &dat
     Here.Add(shift, shift + data.size());
 }
 
-void TBlobState::TState::AddPartToPut(TString &data) {
+void TBlobState::TState::AddPartToPut(TRope &data) {
     Y_VERIFY(data.size());
     Data.SetMonolith(data);
     Here.Assign(0, data.size());
@@ -45,7 +45,7 @@ void TBlobState::AddNeeded(ui64 begin, ui64 size) {
     IsChanged = true;
 }
 
-void TBlobState::AddPartToPut(ui32 partIdx, TString &partData) {
+void TBlobState::AddPartToPut(ui32 partIdx, TRope &partData) {
     Y_VERIFY(bool(Id));
     Y_VERIFY(partIdx < Parts.size());
     Parts[partIdx].AddPartToPut(partData);
@@ -84,17 +84,17 @@ bool TBlobState::Restore(const TBlobStorageGroupInfo &info) {
         if (const ui32 partSize = info.Type.PartSize(TLogoBlobID(Id, i + 1))) {
             if (TIntervalVec<i32>(0, partSize).IsSubsetOf(Parts[i].Here)) {
                 partSet.PartsMask |= (1 << i);
-                TString tmp = TString::Uninitialized(partSize);
-                Parts[i].Data.Read(0, const_cast<char*>(tmp.data()), partSize);
-                partSet.Parts[i].ReferenceTo(tmp);
+                TRope data(MakeIntrusive<TRopeSharedDataBackend>(TSharedData::Uninitialized(partSize)));
+                Parts[i].Data.Read(0, data.UnsafeGetContiguousSpanMut().data(), partSize);
+                partSet.Parts[i].ReferenceTo(data);
             }
         }
     }
     partSet.FullDataSize = Id.BlobSize();
 
-    TString whole;
+    TRope whole;
     info.Type.RestoreData((TErasureType::ECrcMode)Id.CrcMode(), partSet, whole, false, true, false);
-    Whole.Data.Write(0, whole.data(), Id.BlobSize());
+    Whole.Data.Write(0, whole.GetContiguousSpan().data(), Id.BlobSize());
     Whole.Here.Add(fullBlobInterval);
     Whole.NotHere.Subtract(fullBlobInterval);
     return true;
@@ -350,7 +350,7 @@ void TGroupDiskRequests::AddGet(const ui32 diskOrderNumber, const TLogoBlobID &i
     DiskRequestsForOrderNumber[diskOrderNumber].GetsToSend.emplace_back(id, shift, size);
 }
 
-void TGroupDiskRequests::AddPut(const ui32 diskOrderNumber, const TLogoBlobID &id, TString buffer,
+void TGroupDiskRequests::AddPut(const ui32 diskOrderNumber, const TLogoBlobID &id, TRope buffer,
         TDiskPutRequest::EPutReason putReason, bool isHandoff, std::vector<std::pair<ui64, ui32>> *extraBlockChecks,
         NWilson::TSpan *span, ui8 blobIdx) {
     Y_VERIFY(diskOrderNumber < DiskRequestsForOrderNumber.size());
@@ -381,7 +381,7 @@ void TBlackboard::AddNeeded(const TLogoBlobID &id, ui32 inShift, ui32 inSize) {
     }
 }
 
-void TBlackboard::AddPartToPut(const TLogoBlobID &id, ui32 partIdx, TString &partData) {
+void TBlackboard::AddPartToPut(const TLogoBlobID &id, ui32 partIdx, TRope &partData) {
     Y_VERIFY(bool(id));
     Y_VERIFY(id.PartId() == 0);
     Y_VERIFY(id.BlobSize() != 0);
diff --git a/ydb/core/blobstorage/dsproxy/dsproxy_blackboard.h b/ydb/core/blobstorage/dsproxy/dsproxy_blackboard.h
index 72bfd73800c..3108cf0b691 100644
--- a/ydb/core/blobstorage/dsproxy/dsproxy_blackboard.h
+++ b/ydb/core/blobstorage/dsproxy/dsproxy_blackboard.h
@@ -51,7 +51,7 @@ struct TBlobState {
         TIntervalSet<i32> Here;    // Present in the Data buffer
 
         void AddResponseData(ui32 fullSize, ui32 shift, TString &data);
-        void AddPartToPut(TString &data);
+        void AddPartToPut(TRope &data);
         TString ToString() const;
     };
     struct TWholeState : TState {
@@ -88,7 +88,7 @@ struct TBlobState {
 
     void Init(const TLogoBlobID &id, const TBlobStorageGroupInfo &Info);
     void AddNeeded(ui64 begin, ui64 size);
-    void AddPartToPut(ui32 partIdx, TString &partData);
+    void AddPartToPut(ui32 partIdx, TRope &partData);
     void MarkBlobReadyToPut(ui8 blobIdx = 0);
     bool Restore(const TBlobStorageGroupInfo &info);
     void AddResponseData(const TBlobStorageGroupInfo &info, const TLogoBlobID &id, ui32 diskIdxInSubring,
@@ -128,14 +128,14 @@ struct TDiskPutRequest {
         ReasonAccelerate
     };
     const TLogoBlobID Id;
-    TString Buffer;
+    TRope Buffer;
     EPutReason Reason;
     bool IsHandoff;
     ui8 BlobIdx;
     std::vector<std::pair<ui64, ui32>> *ExtraBlockChecks;
     NWilson::TSpan *Span;
 
-    TDiskPutRequest(const TLogoBlobID &id, TString buffer, EPutReason reason, bool isHandoff,
+    TDiskPutRequest(const TLogoBlobID &id, TRope buffer, EPutReason reason, bool isHandoff,
             std::vector<std::pair<ui64, ui32>> *extraBlockChecks, NWilson::TSpan *span, ui8 blobIdx)
         : Id(id)
         , Buffer(std::move(buffer))
@@ -160,7 +160,7 @@ struct TGroupDiskRequests {
     TGroupDiskRequests(ui32 disks);
     void AddGet(const ui32 diskOrderNumber, const TLogoBlobID &id, const TIntervalSet<i32> &intervalSet);
     void AddGet(const ui32 diskOrderNumber, const TLogoBlobID &id, const ui32 shift, const ui32 size);
-    void AddPut(const ui32 diskOrderNumber, const TLogoBlobID &id, TString buffer,
+    void AddPut(const ui32 diskOrderNumber, const TLogoBlobID &id, TRope buffer,
         TDiskPutRequest::EPutReason putReason, bool isHandoff, std::vector<std::pair<ui64, ui32>> *extraBlockChecks,
         NWilson::TSpan *span, ui8 blobIdx);
 };
@@ -205,7 +205,7 @@ struct TBlackboard {
     {}
 
     void AddNeeded(const TLogoBlobID &id, ui32 inShift, ui32 inSize);
-    void AddPartToPut(const TLogoBlobID &id, ui32 partIdx, TString &partData);
+    void AddPartToPut(const TLogoBlobID &id, ui32 partIdx, TRope &partData);
     void MarkBlobReadyToPut(const TLogoBlobID &id, ui8 blobIdx = 0);
     void MoveBlobStateToDone(const TLogoBlobID &id);
     void AddResponseData(const TLogoBlobID &id, ui32 orderNumber, ui32 shift, TString &data, bool keep, bool doNotKeep);
diff --git a/ydb/core/blobstorage/dsproxy/dsproxy_get_impl.cpp b/ydb/core/blobstorage/dsproxy/dsproxy_get_impl.cpp
index cb66db83460..8122e89e909 100644
--- a/ydb/core/blobstorage/dsproxy/dsproxy_get_impl.cpp
+++ b/ydb/core/blobstorage/dsproxy/dsproxy_get_impl.cpp
@@ -364,7 +364,7 @@ void TGetImpl::PrepareVPuts(TLogContext &logCtx,
                 }
                 bytes += put.Buffer.size();
                 lastItemCount++;
-                vMultiPut->AddVPut(put.Id, put.Buffer, &cookie, put.ExtraBlockChecks, NWilson::TTraceId()); // FIXME: trace
+                vMultiPut->AddVPut(put.Id, put.Buffer.ConvertToString(), &cookie, put.ExtraBlockChecks, NWilson::TTraceId()); // FIXME: trace
             }
             vMultiPut->Record.SetCookie(TVMultiPutCookie(diskOrderNumber, lastItemCount, VMultiPutRequests));
             ++VMultiPutRequests;
diff --git a/ydb/core/blobstorage/dsproxy/dsproxy_put.cpp b/ydb/core/blobstorage/dsproxy/dsproxy_put.cpp
index db13013f02b..01dd0a34fa7 100644
--- a/ydb/core/blobstorage/dsproxy/dsproxy_put.cpp
+++ b/ydb/core/blobstorage/dsproxy/dsproxy_put.cpp
@@ -387,14 +387,14 @@ class TBlobStorageGroupPutRequest : public TBlobStorageGroupRequestActor<TBlobSt
             }
             TEvBlobStorage::TEvPut *put;
 
-            TString buffer = item.Buffer;
-            char *data = buffer.Detach();
+            TRope buffer = item.Buffer;
+            char* data = buffer.GetContiguousSpanMut().data();
             Decrypt(data, data, 0, buffer.size(), item.BlobId, *Info);
 
             ev->Bunch.emplace_back(new IEventHandle(
                 TActorId() /*recipient*/,
                 item.Recipient,
-                put = new TEvBlobStorage::TEvPut(item.BlobId, buffer, Deadline, HandleClass, Tactic),
+                put = new TEvBlobStorage::TEvPut(item.BlobId, std::move(buffer), Deadline, HandleClass, Tactic),
                 0 /*flags*/,
                 item.Cookie,
                 nullptr /*forwardOnNondelivery*/,
@@ -545,7 +545,7 @@ public:
             const ui64 partSize = Info->Type.PartSize(blobId);
             ui64 bufferSize = PutImpl.Blobs[idx].BufferSize;
 
-            char *data = PutImpl.Blobs[idx].Buffer.Detach();
+            char *data = PutImpl.Blobs[idx].Buffer.GetContiguousSpanMut().data();
             Encrypt(data, data, 0, bufferSize, blobId, *Info);
             TDataPartSet &partSet = resume->PartSets[idx];
 
@@ -630,9 +630,8 @@ public:
         bool splitDone = true;
         for (ui64 idx = 0; idx < PutImpl.Blobs.size(); ++idx) {
             TDataPartSet &partSet = resume->PartSets[idx];
-            TString &buffer = PutImpl.Blobs[idx].Buffer;
             TLogoBlobID blobId = PutImpl.Blobs[idx].BlobId;
-            Info->Type.IncrementalSplitData((TErasureType::ECrcMode)blobId.CrcMode(), buffer, partSet);
+            Info->Type.IncrementalSplitData((TErasureType::ECrcMode)blobId.CrcMode(), PutImpl.Blobs[idx].Buffer, partSet);
             if (partSet.IsSplitDone()) {
                 ReportBytes(partSet.MemoryConsumed - PutImpl.Blobs[idx].BufferSize);
             } else {
diff --git a/ydb/core/blobstorage/dsproxy/dsproxy_put_impl.h b/ydb/core/blobstorage/dsproxy/dsproxy_put_impl.h
index 2e3ab60fc30..5636a3daf14 100644
--- a/ydb/core/blobstorage/dsproxy/dsproxy_put_impl.h
+++ b/ydb/core/blobstorage/dsproxy/dsproxy_put_impl.h
@@ -46,7 +46,7 @@ private:
 
     struct TBlobInfo {
         TLogoBlobID BlobId;
-        TString Buffer;
+        TRope Buffer;
         ui64 BufferSize;
         TActorId Recipient;
         ui64 Cookie;
@@ -55,7 +55,7 @@ private:
         std::vector<std::pair<ui64, ui32>> ExtraBlockChecks;
         NWilson::TSpan Span;
 
-        TBlobInfo(TLogoBlobID id, TString buffer, TActorId recipient, ui64 cookie, NWilson::TTraceId traceId,
+        TBlobInfo(TLogoBlobID id, TRope&& buffer, TActorId recipient, ui64 cookie, NWilson::TTraceId traceId,
                 NLWTrace::TOrbit&& orbit, std::vector<std::pair<ui64, ui32>> extraBlockChecks, bool single)
             : BlobId(id)
             , Buffer(std::move(buffer))
@@ -115,7 +115,7 @@ public:
         , EnableRequestMod3x3ForMinLatecy(enableRequestMod3x3ForMinLatecy)
         , Tactic(ev->Tactic)
     {
-        Blobs.emplace_back(ev->Id, std::move(ev->Buffer), recipient, cookie, std::move(traceId), std::move(ev->Orbit),
+        Blobs.emplace_back(ev->Id, TRope(ev->Buffer), recipient, cookie, std::move(traceId), std::move(ev->Orbit),
             std::move(ev->ExtraBlockChecks), true);
 
         auto& blob = Blobs.back();
@@ -143,7 +143,7 @@ public:
             auto& msg = *ev->Get();
             Y_VERIFY(msg.HandleClass == putHandleClass);
             Y_VERIFY(msg.Tactic == tactic);
-            Blobs.emplace_back(msg.Id, std::move(msg.Buffer), ev->Sender, ev->Cookie, std::move(ev->TraceId),
+            Blobs.emplace_back(msg.Id, TRope(msg.Buffer), ev->Sender, ev->Cookie, std::move(ev->TraceId),
                 std::move(msg.Orbit), std::move(msg.ExtraBlockChecks), false);
             Deadline = Max(Deadline, msg.Deadline);
 
@@ -496,7 +496,7 @@ protected:
                 } else if constexpr (isVMultiPut) {
                     // this request MUST originate from the TEvPut, so the Span field must be filled in
                     Y_VERIFY(put.Span);
-                    outVPutEvents.back()->AddVPut(put.Id, put.Buffer, &cookie, put.ExtraBlockChecks, put.Span->GetTraceId());
+                    outVPutEvents.back()->AddVPut(put.Id, put.Buffer.ConvertToString(), &cookie, put.ExtraBlockChecks, put.Span->GetTraceId());
                 }
 
                 if (put.IsHandoff) {
diff --git a/ydb/core/blobstorage/dsproxy/dsproxy_strategy_base.cpp b/ydb/core/blobstorage/dsproxy/dsproxy_strategy_base.cpp
index efeedb94465..050b70846ef 100644
--- a/ydb/core/blobstorage/dsproxy/dsproxy_strategy_base.cpp
+++ b/ydb/core/blobstorage/dsproxy/dsproxy_strategy_base.cpp
@@ -291,14 +291,15 @@ void TStrategyBase::PreparePutsForPartPlacement(TLogContext &logCtx, TBlobState
         Y_VERIFY(fullInterval.IsSubsetOf(state.Whole.Here),
                 "Can't put unrestored blob! Unexpected blob state# %s", state.ToString().c_str());
 
-        TString wholeBuffer = TString::Uninitialized(state.Id.BlobSize());
-        state.Whole.Data.Read(0, const_cast<char*>(wholeBuffer.data()), state.Id.BlobSize());
+        TRope wholeBuffer(MakeIntrusive<TRopeSharedDataBackend>(TSharedData::Uninitialized(state.Id.BlobSize())));
+        state.Whole.Data.Read(0, wholeBuffer.UnsafeGetContiguousSpanMut().data(), state.Id.BlobSize());
         TDataPartSet partSet;
         info.Type.SplitData((TErasureType::ECrcMode)state.Id.CrcMode(), wholeBuffer, partSet);
 
         Y_VERIFY(partSet.Parts.size() == state.Parts.size());
         for (ui32 partIdx = 0; partIdx < partSet.Parts.size(); ++partIdx) {
-            state.AddPartToPut(partIdx, partSet.Parts[partIdx].OwnedString);
+            TRope data = partSet.Parts[partIdx].OwnedString;
+            state.AddPartToPut(partIdx, data);
         }
     }
 
diff --git a/ydb/core/blobstorage/dsproxy/dsproxy_strategy_get_min_iops_block.h b/ydb/core/blobstorage/dsproxy/dsproxy_strategy_get_min_iops_block.h
index d191f110060..9297db7a807 100644
--- a/ydb/core/blobstorage/dsproxy/dsproxy_strategy_get_min_iops_block.h
+++ b/ydb/core/blobstorage/dsproxy/dsproxy_strategy_get_min_iops_block.h
@@ -223,7 +223,7 @@ public:
                 }
             }
             partSet.FullDataSize = state.Id.BlobSize();
-            TString whole;
+            TRope whole;
             info.Type.RestoreData((TErasureType::ECrcMode)state.Id.CrcMode(), partSet, whole, false, true, false);
 
             TIntervalSet<i32> missing(state.Whole.NotHere);
@@ -231,7 +231,7 @@ public:
                 auto [begin, end] = *it;
                 i32 offset = begin;
                 i32 size = end - begin;
-                const char *source = whole.data() + offset;
+                const char *source = whole.GetContiguousSpan().data() + offset;
                 // Cerr << "LINE " << __LINE__ << " copy whole [" << offset << ", " << (offset + size) << ")" << Endl;
                 state.Whole.Data.Write(offset, source, size);
                 state.Whole.Here.Add(offset, offset + size);
diff --git a/ydb/core/blobstorage/dsproxy/dsproxy_strategy_put_m3of4.h b/ydb/core/blobstorage/dsproxy/dsproxy_strategy_put_m3of4.h
index 4442c48218b..0fca82976e0 100644
--- a/ydb/core/blobstorage/dsproxy/dsproxy_strategy_put_m3of4.h
+++ b/ydb/core/blobstorage/dsproxy/dsproxy_strategy_put_m3of4.h
@@ -39,7 +39,7 @@ public:
     }
 
 protected:
-    TString GetDataBuffer(TBlobState& state, const TBlobStorageGroupInfo& info) {
+    TRope GetDataBuffer(TBlobState& state, const TBlobStorageGroupInfo& info) {
         for (ui32 i = 0; i < info.Type.TotalPartCount(); ++i) {
             if (info.Type.PartSize(TLogoBlobID(state.Id, i + 1)) && state.Parts[i].Data.IsMonolith()) {
                 return state.Parts[i].Data.GetMonolith();
@@ -47,11 +47,11 @@ protected:
         }
         const TIntervalVec<i32> interval(0, state.Id.BlobSize());
         Y_VERIFY(interval.IsSubsetOf(state.Whole.Here), "missing blob data State# %s", state.ToString().data());
-        TString wholeBuffer = TString::Uninitialized(state.Id.BlobSize());
-        state.Whole.Data.Read(0, const_cast<char*>(wholeBuffer.data()), state.Id.BlobSize());
+        TRope wholeBuffer(MakeIntrusive<TRopeSharedDataBackend>(TSharedData::Uninitialized(state.Id.BlobSize())));
+        state.Whole.Data.Read(0, wholeBuffer.UnsafeGetContiguousSpanMut().data(), state.Id.BlobSize());
         TDataPartSet partSet;
         info.Type.SplitData((TErasureType::ECrcMode)state.Id.CrcMode(), wholeBuffer, partSet);
-        TString s = partSet.Parts[0].OwnedString;
+        TRope s = partSet.Parts[0].OwnedString;
         state.Parts[0].Data.SetMonolith(s);
         return s;
     }
diff --git a/ydb/core/blobstorage/dsproxy/mock/model.h b/ydb/core/blobstorage/dsproxy/mock/model.h
index 16783993f28..ead4f90bb6b 100644
--- a/ydb/core/blobstorage/dsproxy/mock/model.h
+++ b/ydb/core/blobstorage/dsproxy/mock/model.h
@@ -13,11 +13,15 @@ namespace NFake {
         using TStep = ui32;
 
         struct TBlob {
+            TBlob(TRope buffer)
+                : Buffer(std::move(buffer))
+            {}
+
             TBlob(TString buffer)
                 : Buffer(std::move(buffer))
             {}
 
-            TString Buffer;
+            TRope Buffer;
             bool Keep = false;
             bool DoNotKeep = false;
         };
@@ -125,7 +129,7 @@ namespace NFake {
                     const ui32 size = Min<ui32>(maxSize, !query.Size ? Max<ui32>() : query.Size);
 
                     // calculate substring; use 0 instead of query.Shift because it may exceed the buffer
-                    response.Buffer = data.Buffer.substr(size ? query.Shift : 0, size);
+                    response.Buffer = data.Buffer.ConvertToString().substr(size ? query.Shift : 0, size);
                 } else {
                     // ensure this blob is not under GC
                     Y_VERIFY(!IsCollectedByBarrier(id), "Id# %s", id.ToString().data());
@@ -173,7 +177,7 @@ namespace NFake {
                         lastBlobId.Generation() >= msg->MinGeneration) {
                     TString buffer;
                     if (msg->ReadBody) {
-                        buffer = it->second.Buffer;
+                        buffer = it->second.Buffer.ConvertToString();
                     }
 
                     result = std::make_unique<TEvBlobStorage::TEvDiscoverResult>(lastBlobId, msg->MinGeneration, buffer,
@@ -206,7 +210,7 @@ namespace NFake {
             if (from <= to) {
                 // forward scan
                 for (auto it = Blobs.lower_bound(from); it != Blobs.end() && it->first <= to; ++it) {
-                    process(it->first, it->second.Buffer);
+                    process(it->first, it->second.Buffer.ConvertToString());
                 }
             } else {
                 // reverse scan
@@ -215,7 +219,7 @@ namespace NFake {
                     if (it->first < to) {
                         break;
                     } else {
-                        process(it->first, it->second.Buffer);
+                        process(it->first, it->second.Buffer.ConvertToString());
                     }
                 }
             }
diff --git a/ydb/core/blobstorage/dsproxy/ut/dsproxy_fault_tolerance_ut_get_hardened.h b/ydb/core/blobstorage/dsproxy/ut/dsproxy_fault_tolerance_ut_get_hardened.h
index 4c7bd5f1eef..fd7628ef398 100644
--- a/ydb/core/blobstorage/dsproxy/ut/dsproxy_fault_tolerance_ut_get_hardened.h
+++ b/ydb/core/blobstorage/dsproxy/ut/dsproxy_fault_tolerance_ut_get_hardened.h
@@ -305,7 +305,7 @@ public:
             layout.ForEachPartOfDisk(type, [&](ui32 partIdx, ui32 idxInSubgroup) {
                 const TLogoBlobID partId(id, partIdx + 1);
                 const NKikimrProto::EReplyStatus res = PutToVDisk(orderNums[idxInSubgroup], partId,
-                    parts.Parts[partIdx].OwnedString);
+                    parts.Parts[partIdx].OwnedString.ConvertToString());
                 UNIT_ASSERT_VALUES_EQUAL(res, NKikimrProto::OK);
                 disksWrittenTo |= {topology, topology->GetVDiskId(idxInSubgroup)};
             });
diff --git a/ydb/core/blobstorage/dsproxy/ut/dsproxy_patch_ut.cpp b/ydb/core/blobstorage/dsproxy/ut/dsproxy_patch_ut.cpp
index 0e96d053298..deef7756d65 100644
--- a/ydb/core/blobstorage/dsproxy/ut/dsproxy_patch_ut.cpp
+++ b/ydb/core/blobstorage/dsproxy/ut/dsproxy_patch_ut.cpp
@@ -336,7 +336,7 @@ void ConductPut(TTestBasicRuntime &runtime, const TTestArgs &args, ENaivePatchCa
     UNIT_ASSERT_VALUES_EQUAL(put->Id, args.PatchedId);
     UNIT_ASSERT_VALUES_EQUAL(handle->Cookie, args.OriginalId.Hash());
     TString patchedBuffer = MakePatchedBuffer(args);
-    UNIT_ASSERT_VALUES_EQUAL(put->Buffer, patchedBuffer);
+    UNIT_ASSERT_VALUES_EQUAL(put->Buffer.ConvertToString(), patchedBuffer);
 
     std::unique_ptr<TEvBlobStorage::TEvPutResult> putResult = std::make_unique<TEvBlobStorage::TEvPutResult>(
             resultStatus, args.PatchedId, args.StatusFlags, args.CurrentGroupId, args.ApproximateFreeSpaceShare);
diff --git a/ydb/core/blobstorage/dsproxy/ut/dsproxy_vdisk_mock_ut.h b/ydb/core/blobstorage/dsproxy/ut/dsproxy_vdisk_mock_ut.h
index 0a17c046e71..dc095900af2 100644
--- a/ydb/core/blobstorage/dsproxy/ut/dsproxy_vdisk_mock_ut.h
+++ b/ydb/core/blobstorage/dsproxy/ut/dsproxy_vdisk_mock_ut.h
@@ -486,12 +486,12 @@ public:
         Info->Type.SplitData((TErasureType::ECrcMode)id.CrcMode(), encryptedData, partSet);
         for (ui32 i = 0; i < totalParts; ++i) {
             TLogoBlobID pId(id, i + 1);
-            TString pData = partSet.Parts[i].OwnedString;
+            TRope pData = partSet.Parts[i].OwnedString;
             if (i < handoffsToUse) {
                 Y_VERIFY(totalParts + i < totalvd);
-                GetVDisk(vDisksId[totalParts + i].FailDomain, vDisksId[totalParts + i].VDisk).Put(pId, pData);
+                GetVDisk(vDisksId[totalParts + i].FailDomain, vDisksId[totalParts + i].VDisk).Put(pId, pData.ConvertToString());
             } else {
-                GetVDisk(vDisksId[i].FailDomain, vDisksId[i].VDisk).Put(pId, pData);
+                GetVDisk(vDisksId[i].FailDomain, vDisksId[i].VDisk).Put(pId, pData.ConvertToString());
             }
         }
     }
diff --git a/ydb/core/blobstorage/dsproxy/ut_fat/dsproxy_ut.cpp b/ydb/core/blobstorage/dsproxy/ut_fat/dsproxy_ut.cpp
index 43183478c37..07f5948f3ae 100644
--- a/ydb/core/blobstorage/dsproxy/ut_fat/dsproxy_ut.cpp
+++ b/ydb/core/blobstorage/dsproxy/ut_fat/dsproxy_ut.cpp
@@ -1420,7 +1420,7 @@ class TTestBlobStorageProxyVPutVGet : public TTestBlobStorageProxy {
                 TBlobStorageGroupType type(ErasureSpecies);
                 NKikimr::TDataPartSet partSet;
                 type.SplitData((TErasureType::ECrcMode)blobId.CrcMode(), encryptedTestData2, partSet);
-                TEST_RESPONSE(MessageVGetResult, OK, 1, partSet.Parts[0].OwnedString);
+                TEST_RESPONSE(MessageVGetResult, OK, 1, partSet.Parts[0].OwnedString.ConvertToString());
 
                 VERBOSE_COUT("Done");
                 Env->DoneEvent.Signal();
@@ -1713,7 +1713,7 @@ class TTestBlobStorageProxyVGet : public TTestBlobStorageProxy {
                 TBlobStorageGroupType type(ErasureSpecies);
                 NKikimr::TDataPartSet partSet;
                 type.SplitData((TErasureType::ECrcMode)blobId.CrcMode(), encryptedTestData2, partSet);
-                TEST_RESPONSE(MessageVGetResult, OK, 1, partSet.Parts[0].OwnedString);
+                TEST_RESPONSE(MessageVGetResult, OK, 1, partSet.Parts[0].OwnedString.ConvertToString());
 
                 isNoData = false;
                 VERBOSE_COUT("Done");
diff --git a/ydb/core/blobstorage/testload/test_load_vdisk_write.cpp b/ydb/core/blobstorage/testload/test_load_vdisk_write.cpp
index 6cf73e7276b..24e0ccca196 100644
--- a/ydb/core/blobstorage/testload/test_load_vdisk_write.cpp
+++ b/ydb/core/blobstorage/testload/test_load_vdisk_write.cpp
@@ -7,6 +7,7 @@
 #include <ydb/core/base/appdata.h>
 #include <ydb/core/base/interconnect_channels.h>
 #include <library/cpp/monlib/service/pages/templates.h>
+#include <library/cpp/actors/util/rope.h>
 
 namespace NKikimr {
 
@@ -184,7 +185,9 @@ namespace NKikimr {
             }
 
             void IssuePutRequest(const TLogoBlobID& logoBlobId, ui64 cookie, const TActorContext& ctx) {
-                TString whole(logoBlobId.BlobSize(), 'X');
+                TSharedData data = TSharedData::Uninitialized(logoBlobId.BlobSize());
+                std::fill_n(data.mutable_data(), logoBlobId.BlobSize(), 'X');
+                TRope whole(MakeIntrusive<TRopeSharedDataBackend>(data));
                 TDataPartSet parts;
                 GType.SplitData((TErasureType::ECrcMode)logoBlobId.CrcMode(), whole, parts);
                 auto ev = std::make_unique<TEvBlobStorage::TEvVPut>(logoBlobId,
diff --git a/ydb/core/blobstorage/testload/test_load_write.cpp b/ydb/core/blobstorage/testload/test_load_write.cpp
index 01e6839b10e..37de3a35a00 100644
--- a/ydb/core/blobstorage/testload/test_load_write.cpp
+++ b/ydb/core/blobstorage/testload/test_load_write.cpp
@@ -291,7 +291,7 @@ class TLogWriterTestLoadActor : public TActorBootstrapped<TLogWriterTestLoadActo
             const ui32 size = 1;
             const ui32 lastStep = Max<ui32>();
             const TLogoBlobID id(TabletId, Generation, lastStep, Channel, size, 0);
-            const TString buffer = GenerateBuffer(id);
+            const TSharedData buffer = GenerateBuffer<TSharedData>(id);
             auto ev = std::make_unique<TEvBlobStorage::TEvPut>(id, buffer, TInstant::Max(), PutHandleClass);
 
             auto callback = [this] (IEventBase *event, const TActorContext& ctx) {
@@ -531,7 +531,7 @@ class TLogWriterTestLoadActor : public TActorBootstrapped<TLogWriterTestLoadActo
                 putHandleClass = PutHandleClass;
             }
             const TLogoBlobID id(TabletId, Generation, WriteStep, Channel, size, Cookie);
-            const TString buffer = GenerateBuffer(id);
+            const TSharedData buffer = GenerateBuffer<TSharedData>(id);
             auto ev = std::make_unique<TEvBlobStorage::TEvPut>(id, buffer, TInstant::Max(), putHandleClass);
             const ui64 writeQueryId = ++WriteQueryId;
 
@@ -741,8 +741,9 @@ class TLogWriterTestLoadActor : public TActorBootstrapped<TLogWriterTestLoadActo
             NextReadInQueue = false;
         }
 
-        static TString GenerateBuffer(const TLogoBlobID& id) {
-            return GenDataForLZ4(id.BlobSize());
+        template <class ResultContainer = TString>
+        static ResultContainer GenerateBuffer(const TLogoBlobID& id) {
+            return GenDataForLZ4<ResultContainer>(id.BlobSize());
         }
     };
 
diff --git a/ydb/core/blobstorage/ut_blobstorage/main.cpp b/ydb/core/blobstorage/ut_blobstorage/main.cpp
index 1aa4999c8c8..73b302815fd 100644
--- a/ydb/core/blobstorage/ut_blobstorage/main.cpp
+++ b/ydb/core/blobstorage/ut_blobstorage/main.cpp
@@ -66,7 +66,7 @@ Y_UNIT_TEST_SUITE(DonorMode) {
                     break;
                 }
             }
-            TString part = partSet.Parts[blobId.PartId() - 1].OwnedString;
+            TRope part = partSet.Parts[blobId.PartId() - 1].OwnedString;
 
             // scan through existing stored blobs and ensure they are intact
             for (const auto& [blobId, part] : stored) {
@@ -75,19 +75,19 @@ Y_UNIT_TEST_SUITE(DonorMode) {
             }
 
             // add it to stored set
-            stored.emplace(blobId, part);
+            stored.emplace(blobId, part.ConvertToString());
 
             // get the blob location for this group
             const auto& [vdiskActorId, vdiskId] = getBlobLocation(info, blobId);
 
             // first, check that there is no such blob in the disk
-            env.CheckBlob(vdiskActorId, vdiskId, blobId, part, NKikimrProto::NODATA);
+            env.CheckBlob(vdiskActorId, vdiskId, blobId, part.ConvertToString(), NKikimrProto::NODATA);
 
             // put the blob to the disk
-            env.PutBlob(vdiskId, blobId, part);
+            env.PutBlob(vdiskId, blobId, part.ConvertToString());
 
             // check it appeared
-            env.CheckBlob(vdiskActorId, vdiskId, blobId, part);
+            env.CheckBlob(vdiskActorId, vdiskId, blobId, part.ConvertToString());
 
             // wait for sync
             env.WaitForSync(info, blobId);
diff --git a/ydb/core/blobstorage/ut_blobstorage/osiris.cpp b/ydb/core/blobstorage/ut_blobstorage/osiris.cpp
index 989452e3087..432d078bf58 100644
--- a/ydb/core/blobstorage/ut_blobstorage/osiris.cpp
+++ b/ydb/core/blobstorage/ut_blobstorage/osiris.cpp
@@ -43,7 +43,7 @@ bool DoTestCase(TBlobStorageGroupType::EErasureSpecies erasure, const std::set<s
         const TActorId& queueId = env.CreateQueueActor(info->GetVDiskId(orderNum), NKikimrBlobStorage::PutTabletLog, 0);
         const TActorId& sender = env.Runtime->AllocateEdgeActor(queueId.NodeId());
         const TLogoBlobID blobId(id, partIdx + 1);
-        const TString& buffer = type.PartSize(blobId) ? parts.Parts[partIdx].OwnedString : TString();
+        TRope buffer = type.PartSize(blobId) ? parts.Parts[partIdx].OwnedString : TString();
         env.Runtime->Send(new IEventHandle(queueId, sender, new TEvBlobStorage::TEvVPut(blobId, buffer,
             info->GetVDiskId(orderNum), false, nullptr, TInstant::Max(), NKikimrBlobStorage::TabletLog)),
             sender.NodeId());
diff --git a/ydb/core/blobstorage/vdisk/repl/blobstorage_replrecoverymachine.h b/ydb/core/blobstorage/vdisk/repl/blobstorage_replrecoverymachine.h
index 9568165e383..3c13238ad54 100644
--- a/ydb/core/blobstorage/vdisk/repl/blobstorage_replrecoverymachine.h
+++ b/ydb/core/blobstorage/vdisk/repl/blobstorage_replrecoverymachine.h
@@ -206,7 +206,7 @@ namespace NKikimr {
                         Y_VERIFY(partSet.PartSet.FullDataSize == id.BlobSize());
 
                         // PartSet contains some data, other data will be restored and written in the same PartSet
-                        TString recoveredData;
+                        TRope recoveredData;
                         const ui32 incomingMask = partSet.PartSet.PartsMask;
                         if (canRestore && needToRestore) {
                             groupType.RestoreData((TErasureType::ECrcMode)id.CrcMode(), partSet.PartSet, recoveredData,
diff --git a/ydb/core/blobstorage/vdisk/repl/blobstorage_replrecoverymachine_ut.cpp b/ydb/core/blobstorage/vdisk/repl/blobstorage_replrecoverymachine_ut.cpp
index 02e8a077893..83d376047b0 100644
--- a/ydb/core/blobstorage/vdisk/repl/blobstorage_replrecoverymachine_ut.cpp
+++ b/ydb/core/blobstorage/vdisk/repl/blobstorage_replrecoverymachine_ut.cpp
@@ -40,7 +40,7 @@ namespace NKikimr {
                 for (ui32 i = 0; i < info->Type.TotalPartCount(); ++i) {
                     for (ui32 k = 0; k < vdisks.size(); ++k) {
                         if (varray[i] == vdisks[k]) {
-                            diskvec[k] = parts.Parts[i].OwnedString;
+                            diskvec[k] = parts.Parts[i].OwnedString.ConvertToString();
                             break;
                         }
                     }
diff --git a/ydb/core/blobstorage/vdisk/scrub/blob_recovery.h b/ydb/core/blobstorage/vdisk/scrub/blob_recovery.h
index 2a06f7df1ae..57e892ada4d 100644
--- a/ydb/core/blobstorage/vdisk/scrub/blob_recovery.h
+++ b/ydb/core/blobstorage/vdisk/scrub/blob_recovery.h
@@ -48,7 +48,7 @@ namespace NKikimr {
                 Y_VERIFY(id.PartId());
                 const ui32 partIdx = id.PartId() - 1;
                 Y_VERIFY(PartSet.PartsMask & (1 << partIdx));
-                return PartSet.Parts[partIdx].OwnedString;
+                return PartSet.Parts[partIdx].OwnedString.ConvertToString();
             }
 
             NMatrix::TVectorType GetAvailableParts() const {
diff --git a/ydb/core/blobstorage/vdisk/scrub/blob_recovery_process.cpp b/ydb/core/blobstorage/vdisk/scrub/blob_recovery_process.cpp
index 0348ada82de..d78757e78ac 100644
--- a/ydb/core/blobstorage/vdisk/scrub/blob_recovery_process.cpp
+++ b/ydb/core/blobstorage/vdisk/scrub/blob_recovery_process.cpp
@@ -123,7 +123,7 @@ namespace NKikimr {
         }
         const ui32 numParts = PopCount(item.PartSet.PartsMask);
         if (numParts >= Info->Type.MinimalRestorablePartCount()) {
-            TString buffer;
+            TRope buffer;
             Info->Type.RestoreData((TErasureType::ECrcMode)item.BlobId.CrcMode(), item.PartSet, buffer, true,
                 false, true);
             item.PartSet.PartsMask = (1u << item.PartSet.Parts.size()) - 1;
diff --git a/ydb/core/blobstorage/vdisk/scrub/scrub_actor_huge_blob_merger.h b/ydb/core/blobstorage/vdisk/scrub/scrub_actor_huge_blob_merger.h
index 2b04da97606..489a8e97a78 100644
--- a/ydb/core/blobstorage/vdisk/scrub/scrub_actor_huge_blob_merger.h
+++ b/ydb/core/blobstorage/vdisk/scrub/scrub_actor_huge_blob_merger.h
@@ -65,7 +65,7 @@ namespace NKikimr {
                                     key.LogoBlobID());
                                 TRope holder;
                                 TRope part = blob.GetPart(i, &holder);
-                                PartSet.Parts[i].ReferenceTo(part.ConvertToString());
+                                PartSet.Parts[i].ReferenceTo(part);
                             } else {
                                 CorruptedParts.push_back(*part);
                             }
diff --git a/ydb/core/blobstorage/vdisk/skeleton/skeleton_vpatch_actor_ut.cpp b/ydb/core/blobstorage/vdisk/skeleton/skeleton_vpatch_actor_ut.cpp
index cb9f9708a11..7e8e7244756 100644
--- a/ydb/core/blobstorage/vdisk/skeleton/skeleton_vpatch_actor_ut.cpp
+++ b/ydb/core/blobstorage/vdisk/skeleton/skeleton_vpatch_actor_ut.cpp
@@ -229,6 +229,12 @@ namespace NKikimr {
             {
             }
 
+            TBlob(const TLogoBlobID &blob, ui8 partId, const TRope &buffer)
+                : BlobId(blob, partId)
+                , Buffer(buffer.ConvertToString())
+            {
+            }
+
             TBlob(const TLogoBlobID &blob, ui8 partId, ui32 bufferSize)
                 : BlobId(blob, partId)
             {
@@ -759,7 +765,7 @@ namespace NKikimr {
                     ui32 patchedPartId = LogoBlobIDFromLogoBlobID(record.GetPatchedPartBlobId()).PartId();
 
                     TVector<TDiff> xorDiffs;
-                    const ui8 *buffer = reinterpret_cast<const ui8*>(partSet.Parts[fromPartId - 1].OwnedString.data());
+                    const ui8 *buffer = reinterpret_cast<const ui8*>(partSet.Parts[fromPartId - 1].OwnedString.GetContiguousSpan().data());
                     testData.GType.MakeXorDiff(TErasureType::CrcModeNone, data.size(), buffer, diffSet.PartDiffs[fromPartId - 1].Diffs, &xorDiffs);
 
                     UNIT_ASSERT_VALUES_EQUAL_C(xorDiffs.size(), record.DiffsSize(), "from# " << (ui32)fromPartId);
diff --git a/ydb/core/erasure/erasure.cpp b/ydb/core/erasure/erasure.cpp
index a41b0279328..fc1d8e8a206 100644
--- a/ydb/core/erasure/erasure.cpp
+++ b/ydb/core/erasure/erasure.cpp
@@ -44,7 +44,7 @@ static TString DebugFormatBits(ui64 value) {
 
 namespace NKikimr {
 
-static void Refurbish(TString &str, ui64 size) {
+static void Refurbish(TRope &str, ui64 size) {
     if (str.size() != size) {
         str = TString::Uninitialized(size);
     }
@@ -1378,12 +1378,12 @@ void PadAndCrcParts(TErasureType::ECrcMode crcMode, const TBlockParams &p, TData
 }
 
 template <bool isStripe>
-void StarBlockSplit(TErasureType::ECrcMode crcMode, const TErasureType &type, const TString &buffer,
+void StarBlockSplit(TErasureType::ECrcMode crcMode, const TErasureType &type, TRope &buffer,
         TDataPartSet &outPartSet) {
     TBlockParams p(crcMode, type, buffer.size());
 
     // Prepare input data pointers
-    p.PrepareInputDataPointers<isStripe>(const_cast<char*>(buffer.data()));
+    p.PrepareInputDataPointers<isStripe>(buffer.UnsafeGetContiguousSpanMut().data());
 
     outPartSet.FullDataSize = buffer.size();
     outPartSet.PartsMask = ~((~(ui32)0) << p.TotalParts);
@@ -1399,12 +1399,12 @@ void StarBlockSplit(TErasureType::ECrcMode crcMode, const TErasureType &type, co
 }
 
 template <bool isStripe>
-void EoBlockSplit(TErasureType::ECrcMode crcMode, const TErasureType &type, const TString &buffer,
+void EoBlockSplit(TErasureType::ECrcMode crcMode, const TErasureType &type, TRope &buffer,
         TDataPartSet &outPartSet) {
     TBlockParams p(crcMode, type, buffer.size());
 
     // Prepare input data pointers
-    p.PrepareInputDataPointers<isStripe>(const_cast<char*>(buffer.data()));
+    p.PrepareInputDataPointers<isStripe>(buffer.UnsafeGetContiguousSpanMut().data());
 
     // Prepare if not yet
     if (!outPartSet.IsSplitStarted()) {
@@ -1429,12 +1429,12 @@ void EoBlockSplit(TErasureType::ECrcMode crcMode, const TErasureType &type, cons
 }
 
 template <bool isStripe>
-void XorBlockSplit(TErasureType::ECrcMode crcMode, const TErasureType &type, const TString& buffer,
+void XorBlockSplit(TErasureType::ECrcMode crcMode, const TErasureType &type, TRope& buffer,
         TDataPartSet& outPartSet) {
     TBlockParams p(crcMode, type, buffer.size());
 
     // Prepare input data pointers
-    p.PrepareInputDataPointers<isStripe>(const_cast<char*>(buffer.data()));
+    p.PrepareInputDataPointers<isStripe>(buffer.UnsafeGetContiguousSpanMut().data());
 
     outPartSet.FullDataSize = buffer.size();
     outPartSet.PartsMask = ~((~(ui32)0) << p.TotalParts);
@@ -1451,7 +1451,7 @@ void XorBlockSplit(TErasureType::ECrcMode crcMode, const TErasureType &type, con
 
 template <bool isStripe, bool restoreParts, bool restoreFullData, bool restoreParityParts>
 void EoBlockRestore(TErasureType::ECrcMode crcMode, const TErasureType &type, TDataPartSet& partSet) {
-    TString &outBuffer = partSet.FullDataFragment.OwnedString;
+    TRope &outBuffer = partSet.FullDataFragment.OwnedString;
     ui32 totalParts = type.TotalPartCount();
     Y_VERIFY(partSet.Parts.size() >= totalParts);
 
@@ -1515,17 +1515,17 @@ void EoBlockRestore(TErasureType::ECrcMode crcMode, const TErasureType &type, TD
                 (!restoreParts && missingDataPartIdxA >= p.TotalParts - 2)) {
         VERBOSE_COUT(__LINE__ << " of " << __FILE__ << Endl);
         if (isStripe) {
-            p.PrepareInputDataPointers<isStripe>(outBuffer.Detach());
+            p.PrepareInputDataPointers<isStripe>(outBuffer.GetContiguousSpanMut().data());
             p.XorRestorePart<isStripe, false, true, false>(partSet, p.DataParts);
         } else {
-            p.GlueBlockParts(outBuffer.Detach(), partSet);
+            p.GlueBlockParts(outBuffer.GetContiguousSpanMut().data(), partSet);
         }
         return;
     }
 
     // Prepare output data pointers
     if (restoreFullData) {
-        p.PrepareInputDataPointers<isStripe>(outBuffer.Detach());
+        p.PrepareInputDataPointers<isStripe>(outBuffer.GetContiguousSpanMut().data());
     }
 
     // Consider failed disk cases
@@ -1541,15 +1541,15 @@ void EoBlockRestore(TErasureType::ECrcMode crcMode, const TErasureType &type, TD
     //    TODO: use 2-nd part of 'eo-split' to restore m+1 part
     //    TODO: 1-pass
     if (missingDataPartIdxA <= p.DataParts && missingDataPartIdxB >= p.TotalParts - 1) {
-        TString temp;
-        TString &buffer = restoreFullData ? outBuffer : temp;
+        TRope temp;
+        TRope &buffer = restoreFullData ? outBuffer : temp;
         if (!restoreFullData && restoreParts && missingDataPartIdxB == p.TotalParts - 1) {
             // The (f1) case, but no full data needed, only parts
             TRACE("case# f1" << Endl);
             VERBOSE_COUT(__LINE__ << " of " << __FILE__ << Endl);
             if (isStripe) {
                 Refurbish(buffer, dataSize);
-                p.PrepareInputDataPointers<isStripe>(buffer.Detach());
+                p.PrepareInputDataPointers<isStripe>(buffer.GetContiguousSpanMut().data());
             }
             p.XorRestorePart<isStripe, true, false, false>(partSet, missingDataPartIdxA);
             TRACE("case# f1 split" << Endl);
@@ -1583,8 +1583,8 @@ void EoBlockRestore(TErasureType::ECrcMode crcMode, const TErasureType &type, TD
     if (missingDataPartIdxA == p.TotalParts - 1 && missingDataPartIdxB == p.TotalParts) {
         TRACE("case# c" << Endl);
         VERBOSE_COUT(__LINE__ << " of " << __FILE__ << Endl);
-        TString temp;
-        TString &buffer = restoreFullData ? outBuffer : temp;
+        TRope temp;
+        TRope &buffer = restoreFullData ? outBuffer : temp;
         if (!restoreFullData) {
             TRACE(__LINE__ << Endl);
             if (!restoreParityParts) {
@@ -1598,12 +1598,12 @@ void EoBlockRestore(TErasureType::ECrcMode crcMode, const TErasureType &type, TD
         }
         if (isStripe) {
             TRACE(__LINE__ << Endl);
-            p.PrepareInputDataPointers<isStripe>(buffer.Detach());
+            p.PrepareInputDataPointers<isStripe>(buffer.GetContiguousSpanMut().data());
             p.XorRestorePart<isStripe, false, true, false>(partSet, p.DataParts);
         } else {
             TRACE(__LINE__ << Endl);
             if (restoreFullData) {
-                p.GlueBlockParts(buffer.Detach(), partSet);
+                p.GlueBlockParts(buffer.GetContiguousSpanMut().data(), partSet);
             }
         }
         if (restoreParts) {
@@ -1650,7 +1650,7 @@ void EoBlockRestore(TErasureType::ECrcMode crcMode, const TErasureType &type, TD
 // restorePartiyParts may be set only togehter with restore parts
 template <bool isStripe, bool restoreParts, bool restoreFullData, bool restoreParityParts>
 void StarBlockRestore(TErasureType::ECrcMode crcMode, const TErasureType &type, TDataPartSet& partSet) {
-    TString &outBuffer = partSet.FullDataFragment.OwnedString;
+    TRope &outBuffer = partSet.FullDataFragment.OwnedString;
 
     ui32 totalParts = type.TotalPartCount();
     Y_VERIFY(partSet.Parts.size() == totalParts);
@@ -1728,7 +1728,7 @@ void StarBlockRestore(TErasureType::ECrcMode crcMode, const TErasureType &type,
     TBlockParams p(crcMode, type, dataSize);
     if (restoreFullData) {
         Refurbish(outBuffer, dataSize);
-        p.PrepareInputDataPointers<isStripe>(outBuffer.Detach());
+        p.PrepareInputDataPointers<isStripe>(outBuffer.GetContiguousSpanMut().data());
     } else if (missingDataPartCount == 0) {
         return;
     }
@@ -1738,10 +1738,10 @@ void StarBlockRestore(TErasureType::ECrcMode crcMode, const TErasureType &type,
             (!restoreParts && missingDataPartIdxA >= p.DataParts)) {
         VERBOSE_COUT(__LINE__ << " of " << __FILE__ << Endl);
         if (isStripe) {
-            p.PrepareInputDataPointers<isStripe>(outBuffer.Detach());
+            p.PrepareInputDataPointers<isStripe>(outBuffer.GetContiguousSpanMut().data());
             p.XorRestorePart<isStripe, false, true, false>(partSet, p.DataParts);
         } else {
-            p.GlueBlockParts(outBuffer.Detach(), partSet);
+            p.GlueBlockParts(outBuffer.GetContiguousSpanMut().data(), partSet);
         }
         return;
     }
@@ -1880,7 +1880,7 @@ void StarBlockRestore(TErasureType::ECrcMode crcMode, const TErasureType &type,
 
 template <bool isStripe, bool restoreParts, bool restoreFullData, bool restoreParityParts>
 void XorBlockRestore(TErasureType::ECrcMode crcMode, const TErasureType &type, TDataPartSet &partSet) {
-    TString &outBuffer = partSet.FullDataFragment.OwnedString;
+    TRope &outBuffer = partSet.FullDataFragment.OwnedString;
     ui32 totalParts = type.TotalPartCount();
     Y_VERIFY(partSet.Parts.size() == totalParts,
         "partSet.Parts.size(): %" PRIu64 " totalParts: %" PRIu32 " erasure: %s",
@@ -1919,16 +1919,16 @@ void XorBlockRestore(TErasureType::ECrcMode crcMode, const TErasureType &type, T
     if (missingDataPartCount == 0 ||
             (missingDataPartCount == 1 && !restoreParts && missingDataPartIdx == p.TotalParts - 1)) {
         if (isStripe) {
-            p.PrepareInputDataPointers<isStripe>(outBuffer.Detach());
+            p.PrepareInputDataPointers<isStripe>(outBuffer.GetContiguousSpanMut().data());
             p.XorRestorePart<isStripe, false, true, false>(partSet, p.DataParts);
         } else {
-            p.GlueBlockParts(outBuffer.Detach(), partSet);
+            p.GlueBlockParts(outBuffer.GetContiguousSpanMut().data(), partSet);
         }
         return;
     }
     // Prepare output data pointers
     if (restoreFullData) {
-        p.PrepareInputDataPointers<isStripe>(outBuffer.Detach());
+        p.PrepareInputDataPointers<isStripe>(outBuffer.GetContiguousSpanMut().data());
     }
 
     p.XorRestorePart<isStripe, restoreParts, restoreFullData, restoreParityParts>(partSet, missingDataPartIdx);
@@ -2502,7 +2502,7 @@ ui64 TErasureType::BlockSplitPartUsedSize(ui64 dataSize, ui32 partIdx) const {
     return lastPartSize;
 }
 
-void MirrorSplit(TErasureType::ECrcMode crcMode, const TErasureType &type, const TString& buffer,
+void MirrorSplit(TErasureType::ECrcMode crcMode, const TErasureType &type, TRope& buffer,
         TDataPartSet& outPartSet) {
     outPartSet.FullDataSize = buffer.size();
     outPartSet.Parts.resize(type.TotalPartCount());
@@ -2519,12 +2519,12 @@ void MirrorSplit(TErasureType::ECrcMode crcMode, const TErasureType &type, const
     case TErasureType::CrcModeWholePart:
         {
             ui64 partSize = type.PartSize(crcMode, buffer.size());
-            TString part = TString::Uninitialized(partSize);
-            char *dst = part.Detach();
+            TRope part = TString::Uninitialized(partSize);
+            char *dst = part.GetContiguousSpanMut().data();
             if (buffer.size() || part.size()) {
                 Y_VERIFY(part.size() >= buffer.size() + sizeof(ui32), "Part size too small, buffer size# %" PRIu64
                         " partSize# %" PRIu64, (ui64)buffer.size(), (ui64)partSize);
-                memcpy(dst, buffer.data(), buffer.size());
+                memcpy(dst, buffer.GetContiguousSpan().data(), buffer.size());
                 PadAndCrcAtTheEnd(dst, buffer.size(), part.size());
             }
             for (ui32 partIdx = 0; partIdx <= parityParts; ++partIdx) {
@@ -2558,11 +2558,15 @@ void MirrorRestore(TErasureType::ECrcMode crcMode, const TErasureType &type, TDa
                         partSet.FullDataFragment.ReferenceTo(partSet.Parts[partIdx].OwnedString);
                         return;
                     case TErasureType::CrcModeWholePart:
-                        TString outBuffer = partSet.Parts[partIdx].OwnedString;
-                        outBuffer.Detach();
-                        Y_VERIFY(outBuffer.size() >= partSet.FullDataSize, "Unexpected outBuffer.size# %" PRIu64
-                                " fullDataSize# %" PRIu64, (ui64)outBuffer.size(), (ui64)partSet.FullDataSize);
-                        outBuffer.resize(partSet.FullDataSize); // To pad with zeroes!
+                        TRope outBuffer = partSet.Parts[partIdx].OwnedString;
+                        outBuffer.GetContiguousSpanMut(); // Detach
+                        if(outBuffer.size() != partSet.FullDataSize) {
+                            TString newOutBuffer(outBuffer.GetContiguousSpan().data(), outBuffer.size()); //FIXME(innokentii) potentially redundant allocation for resize
+                            Y_VERIFY(outBuffer.size() >= partSet.FullDataSize, "Unexpected outBuffer.size# %" PRIu64
+                                    " fullDataSize# %" PRIu64, (ui64)outBuffer.size(), (ui64)partSet.FullDataSize);
+                            newOutBuffer.resize(partSet.FullDataSize); // To pad with zeroes!
+                            outBuffer = newOutBuffer;
+                        }
                         partSet.FullDataFragment.ReferenceTo(outBuffer);
                         return;
                 }
@@ -2586,14 +2590,14 @@ static void VerifyPartSizes(TDataPartSet& partSet, size_t definedPartEndIdx) {
     }
 }
 
-void TErasureType::SplitData(ECrcMode crcMode, const TString& buffer, TDataPartSet& outPartSet) const {
+void TErasureType::SplitData(ECrcMode crcMode, TRope& buffer, TDataPartSet& outPartSet) const {
     outPartSet.ResetSplit();
     do {
         IncrementalSplitData(crcMode, buffer, outPartSet);
     } while (!outPartSet.IsSplitDone());
 }
 
-void TErasureType::IncrementalSplitData(ECrcMode crcMode, const TString& buffer, TDataPartSet& outPartSet) const {
+void TErasureType::IncrementalSplitData(ECrcMode crcMode, TRope& buffer, TDataPartSet& outPartSet) const {
     const TErasureParameters& erasure = ErasureSpeciesParameters[ErasureSpecies];
     switch (erasure.ErasureFamily) {
         case TErasureType::ErasureMirror:
@@ -2968,7 +2972,7 @@ void TErasureType::ApplyXorDiff(ECrcMode crcMode, ui32 dataSize, ui8 *dst,
     }
 }
 
-void TErasureType::RestoreData(ECrcMode crcMode, TDataPartSet& partSet, TString& outBuffer, bool restoreParts,
+void TErasureType::RestoreData(ECrcMode crcMode, TDataPartSet& partSet, TRope& outBuffer, bool restoreParts,
         bool restoreFullData, bool restoreParityParts) const {
     partSet.FullDataFragment.ReferenceTo(outBuffer);
     RestoreData(crcMode, partSet, restoreParts, restoreFullData, restoreParityParts);
diff --git a/ydb/core/erasure/erasure.h b/ydb/core/erasure/erasure.h
index 35bd68c2d2f..d7d4da114b8 100644
--- a/ydb/core/erasure/erasure.h
+++ b/ydb/core/erasure/erasure.h
@@ -12,6 +12,7 @@
 
 #include <util/generic/list.h>
 #include <library/cpp/containers/stack_vector/stack_vec.h>
+#include <library/cpp/actors/util/rope.h>
 
 namespace NKikimr {
 
@@ -57,7 +58,7 @@ struct TPartDiffSet {
 
 // Part fragment, contains only some data
 struct TPartFragment {
-    TString OwnedString; // Used for ownership only
+    TRope OwnedString; // Used for ownership only
     char *Bytes = nullptr;
     ui64 Offset = 0; // Relative to part beginning
     ui64 Size = 0;
@@ -76,32 +77,34 @@ struct TPartFragment {
     }
 
     void UninitializedOwnedWhole(ui64 size) {
-        OwnedString = TString::Uninitialized(size);
-        Bytes = OwnedString.Detach();
+        OwnedString = TString::Uninitialized(size); //FIXME(innokentii)
+        Bytes = OwnedString.GetContiguousSpanMut().data();
         Offset = 0;
         Size = size;
         PartSize = size;
     }
 
-    void ResetToWhole(const TString &whole) {
+    void ResetToWhole(const TRope &whole) {
         OwnedString = whole;
-        Bytes = OwnedString.Detach();
+        Bytes = OwnedString.GetContiguousSpanMut().data();
         Offset = 0;
-        Size = whole.size();
+        Size = OwnedString.size();
         PartSize = Size;
     }
 
-    void ReferenceTo(const TString &whole) {
+    void ReferenceTo(const TRope &whole) {
+        Y_VERIFY(whole.IsContiguous());
         OwnedString = whole;
-        Bytes = const_cast<char*>(whole.data());
+        Bytes = OwnedString.UnsafeGetContiguousSpanMut().data();
         Offset = 0;
-        Size = whole.size();
+        Size = OwnedString.size();
         PartSize = Size;
     }
 
-    void ReferenceTo(const TString &piece, ui64 offset, ui64 size, ui64 partSize) {
+    void ReferenceTo(const TRope &piece, ui64 offset, ui64 size, ui64 partSize) {
+        Y_VERIFY(piece.IsContiguous());
         OwnedString = piece;
-        Bytes = const_cast<char*>(piece.data());
+        Bytes = OwnedString.UnsafeGetContiguousSpanMut().data();
         Offset = offset;
         Y_VERIFY(size <= piece.size());
         Size = size;
@@ -109,6 +112,17 @@ struct TPartFragment {
         PartSize = partSize;
     }
 
+    void ReferenceTo(const TString &whole) {
+        TRope rope(whole);
+        ReferenceTo(rope);
+    }
+
+    void ReferenceTo(const TString &piece, ui64 offset, ui64 size, ui64 partSize) {
+        TRope rope(piece);
+        ReferenceTo(rope, offset, size, partSize);
+    }
+
+
     char *GetDataAt(ui64 get_offset) const {
         Y_VERIFY_DEBUG(Size);
         Y_VERIFY_DEBUG(get_offset >= Offset, "%s", (TStringBuilder() << "get_offset# " << get_offset
@@ -130,19 +144,12 @@ struct TPartFragment {
     }
 
     void Detach() {
-        char *newBytes = nullptr;
-        if (Bytes) {
+        if(Bytes) {
             char *oldBytes = Bytes;
-            char *oldData = const_cast<char*>(OwnedString.data());
+            char *oldData = OwnedString.UnsafeGetContiguousSpanMut().data();
             intptr_t bytesOffset = oldBytes - oldData;
-            OwnedString.Detach();
-            if (OwnedString.data() != oldData) {
-                newBytes = const_cast<char*>(OwnedString.data()) + bytesOffset;
-            } else {
-                newBytes = oldBytes;
-            }
+            Bytes = OwnedString.GetContiguousSpanMut().data() + bytesOffset;
         }
-        Bytes = newBytes;
     }
 };
 
@@ -317,8 +324,16 @@ struct TErasureType {
     ui64 SuggestDataSize(ECrcMode crcMode, ui64 partSize, bool roundDown) const;
     ui32 Prime() const;
 
-    void SplitData(ECrcMode crcMode, const TString& buffer, TDataPartSet& outPartSet) const;
-    void IncrementalSplitData(ECrcMode crcMode, const TString& buffer, TDataPartSet& outPartSet) const;
+    void SplitData(ECrcMode crcMode, TRope& buffer, TDataPartSet& outPartSet) const;
+    void SplitData(ECrcMode crcMode, const TString& buffer, TDataPartSet& outPartSet) const {
+        TRope rope = buffer;
+        SplitData(crcMode, rope, outPartSet);
+    }
+    void IncrementalSplitData(ECrcMode crcMode, TRope& buffer, TDataPartSet& outPartSet) const;
+    void IncrementalSplitData(ECrcMode crcMode, const TString& buffer, TDataPartSet& outPartSet) const {
+        TRope rope = buffer;
+        IncrementalSplitData(crcMode, rope, outPartSet);
+    }
 
     void SplitDiffs(ECrcMode crcMode, ui32 dataSize, const TVector<TDiff> &diffs, TPartDiffSet& outDiffSet) const;
     void ApplyDiff(ECrcMode crcMode, ui8 *dst, const TVector<TDiff> &diffs) const;
@@ -327,7 +342,7 @@ struct TErasureType {
     void ApplyXorDiff(ECrcMode crcMode, ui32 dataSize, ui8 *dst,
             const TVector<TDiff> &diffs, ui8 fromPart, ui8 toPart) const;
 
-    void RestoreData(ECrcMode crcMode, TDataPartSet& partSet, TString& outBuffer, bool restoreParts,
+    void RestoreData(ECrcMode crcMode, TDataPartSet& partSet, TRope& outBuffer, bool restoreParts,
             bool restoreFullData, bool restoreParityParts) const;
     void RestoreData(ECrcMode crcMode, TDataPartSet& partSet, bool restoreParts, bool restoreFullData,
             bool restoreParityParts) const;
diff --git a/ydb/core/erasure/erasure_perf_test.cpp b/ydb/core/erasure/erasure_perf_test.cpp
index 37b1a3bab64..ae4c79c946f 100644
--- a/ydb/core/erasure/erasure_perf_test.cpp
+++ b/ydb/core/erasure/erasure_perf_test.cpp
@@ -99,7 +99,10 @@ std::pair<double, double> MeasureTime(TErasureType &type, TVector<ui32> &missedP
             const ui32 partSize = type.PartSize(TErasureType::CrcModeNone, dataSize);
             partSet.Parts.resize(type.TotalPartCount());
             for (ui32 i = 0; i < type.TotalPartCount(); ++i) {
-                partSet.Parts[i].ReferenceTo(partSet.Parts[i].OwnedString.resize(partSize));
+                auto data = partSet.Parts[i].OwnedString.GetContiguousSpan();
+                TString newOwnedString(partSize, '\0');
+                memcpy(newOwnedString.Detach(), data.data(), data.size());
+                partSet.Parts[i].ReferenceTo(partSet.Parts[i].OwnedString);
             }
         }
         if (measureSplit) {
@@ -113,13 +116,10 @@ std::pair<double, double> MeasureTime(TErasureType &type, TVector<ui32> &missedP
             time += timer.PassedReset() / attempts;
         }
         if (isRestoreFullData) {
-            std::vector<TString> restoredData;
+            std::vector<TRope> restoredData;
             restoredData.resize(attempts);
             for (auto& restored : restoredData) {
-                restored.resize(dataSize);
-                for (ui64 i = 0; i < dataSize; ++i) {
-                    restored[i] = 0;
-                }
+                restored = TString(dataSize, '\0');
             }
             // Remove the 'missing' parts
             for (auto& partSet : partSets) {
@@ -136,7 +136,7 @@ std::pair<double, double> MeasureTime(TErasureType &type, TVector<ui32> &missedP
                 time += timer.PassedReset() / attempts;
             }
             for (size_t i = 0; i < attempts; ++i) {
-                UNIT_ASSERT_EQUAL(originalData[i], restoredData[i]);
+                UNIT_ASSERT_EQUAL(TRope(originalData[i]), restoredData[i]);
             }
         }
         times.push_back(time);
@@ -250,7 +250,7 @@ void RopeMeasureSplitTime(TErasureType &type, ui64 dataSize, const TString& buff
         type.SplitData(TErasureType::CrcModeNone, rope, partSet);
         if (convertToRope) {
             for (int i = 0; i < 6; ++i) {
-                ropes[i] = RopeFromStringReference(std::move(partSet.Parts[i].OwnedString));
+                ropes[i] = partSet.Parts[i].OwnedString;
             }
         }
 #ifdef LONG_TEST
diff --git a/ydb/core/erasure/erasure_ut.cpp b/ydb/core/erasure/erasure_ut.cpp
index 2473bd16506..731230ff304 100644
--- a/ydb/core/erasure/erasure_ut.cpp
+++ b/ydb/core/erasure/erasure_ut.cpp
@@ -48,7 +48,7 @@ void TestMissingPartWithRandomData(TErasureType &groupType, ui32 *missingPartIdx
         partSet.Parts[missingPartIdx[i]].clear();
     }
     // Restore the data
-    TString restoredString;
+    TRope restoredString;
     groupType.RestoreData(TErasureType::CrcModeNone, partSet, restoredString,
             isRestoreParts, isRestoreFullData, isRestoreParts);
 
@@ -191,7 +191,7 @@ void RunTestDiff(TErasureType &groupType, ui32 dataSize, const TString &testStri
     }
 
     for (ui32 partIdx = 0; partIdx < dataParts + parityParts; ++partIdx) {
-        UNIT_ASSERT_STRINGS_EQUAL(partSet.Parts[partIdx].OwnedString, resultPartSet.Parts[partIdx].OwnedString);
+        UNIT_ASSERT_STRINGS_EQUAL(partSet.Parts[partIdx].OwnedString.ConvertToString(), resultPartSet.Parts[partIdx].OwnedString.ConvertToString());
     }
 }
 
@@ -298,7 +298,7 @@ Y_UNIT_TEST_SUITE(TErasureTypeTest) {
                 UNIT_ASSERT_EQUAL_C(partSet.Parts[i].size(), expectedParts[i].size(), Sprintf("%lu == %lu",
                                                                 partSet.Parts[i].size(), expectedParts[i].size()));
                 for (ui32 j = 0; j < partSet.Parts[i].size(); ++j) {
-                    UNIT_ASSERT_EQUAL( (ui8)partSet.Parts[i].OwnedString[j], expectedParts[i][j]);
+                    UNIT_ASSERT_EQUAL( (ui8)partSet.Parts[i].OwnedString.GetContiguousSpan().data()[j], expectedParts[i][j]);
                 }
             }
         }
@@ -391,7 +391,7 @@ Y_UNIT_TEST_SUITE(TErasureTypeTest) {
                             (isRestoreParts ? "true" : "false"),
                             (isRestoreFullData ? "true" : "false"));
 
-                        TString restoredString;
+                        TRope restoredString;
                         try {
                             groupType.RestoreData(TErasureType::CrcModeNone, partSet, restoredString,
                                     isRestoreParts, isRestoreFullData, isRestoreParts);
@@ -404,9 +404,9 @@ Y_UNIT_TEST_SUITE(TErasureTypeTest) {
                         if (isRestoreFullData) {
                             UNIT_ASSERT_EQUAL_C(testString.size(), restoredString.size(), errorInfo);
                             for (ui32 i = 0; i < testString.size(); ++i) {
-                                UNIT_ASSERT_EQUAL_C(((char*)testString.data())[i], ((char*)restoredString.data())[i],
+                                UNIT_ASSERT_EQUAL_C(((char*)testString.data())[i], (restoredString.UnsafeGetContiguousSpanMut().data())[i],
                                     (errorInfo + mode + " (full data)"));
-                                if (((char*)testString.data())[i] != ((char*)restoredString.data())[i]) {
+                                if (((char*)testString.data())[i] != (restoredString.UnsafeGetContiguousSpanMut().data())[i]) {
                                     VERBOSE_COUT("mismatch " << errorInfo << mode << " (full data)" << Endl);
                                     break;
                                 }
@@ -711,7 +711,7 @@ Y_UNIT_TEST_SUITE(TErasureTypeTest) {
                             partSet.Parts[missingPartIdx[idx]].clear();
                         }
                     }
-                    partSet.FullDataFragment.UninitializedOwnedWhole(dataSize);;
+                    partSet.FullDataFragment.UninitializedOwnedWhole(dataSize);
 
 
                     TString mode = Sprintf(" restoreParts=%s isRestoreParityParts=%s restoreFullData=%s ",
@@ -720,7 +720,7 @@ Y_UNIT_TEST_SUITE(TErasureTypeTest) {
                         (isRestoreFullData ? "true" : "false"));
 
                     VERBOSE_COUT("RestoreData " << errorInfo << Endl);
-                    TString restoredString;
+                    TRope restoredString;
                     try {
                         groupType.RestoreData(crcMode, partSet, restoredString,
                                 isRestoreParts, isRestoreFullData, isRestoreParityParts);
@@ -733,7 +733,7 @@ Y_UNIT_TEST_SUITE(TErasureTypeTest) {
                     if (isRestoreFullData) {
                         UNIT_ASSERT_EQUAL_C(testString.size(), restoredString.size(), errorInfo);
                         for (ui32 i = 0; i < testString.size(); ++i) {
-                            UNIT_ASSERT_EQUAL_C(((char*)testString.data())[i], ((char*)restoredString.data())[i],
+                            UNIT_ASSERT_EQUAL_C(((char*)testString.data())[i], (restoredString.UnsafeGetContiguousSpanMut().data())[i],
                                 (errorInfo + erasureName + mode + " (full data)"));
                         }
                     }
@@ -1036,7 +1036,7 @@ Y_UNIT_TEST_SUITE(TErasureTypeTest) {
                     for (ui32 idx = 0; idx < partSet.Parts.size(); ++idx) {
                         ui32 cutBegin = Min(partSize, needBegin);
                         ui32 cutSize = Min(partSize, needEnd) - cutBegin;
-                        partSet.Parts[idx].ReferenceTo(partSet.Parts[idx].OwnedString.substr(cutBegin, cutSize),
+                        partSet.Parts[idx].ReferenceTo(partSet.Parts[idx].OwnedString.ConvertToString().substr(cutBegin, cutSize),
                                 cutBegin, cutSize, partSize);
                     }
 
diff --git a/ydb/core/util/defs.h b/ydb/core/util/defs.h
index 04dab350864..b587a43d7db 100644
--- a/ydb/core/util/defs.h
+++ b/ydb/core/util/defs.h
@@ -17,3 +17,7 @@
 #include <util/generic/vector.h>
 #include <util/datetime/base.h>
 #include <util/generic/ylimits.h>
+
+namespace NKikimr {
+using namespace NActors;
+} // namespace NKikimr
diff --git a/ydb/core/util/fragmented_buffer.cpp b/ydb/core/util/fragmented_buffer.cpp
index 6da04399b60..3ae32c380ef 100644
--- a/ydb/core/util/fragmented_buffer.cpp
+++ b/ydb/core/util/fragmented_buffer.cpp
@@ -1,6 +1,7 @@
 #include "fragmented_buffer.h"
 
 #include <util/stream/str.h>
+#include <library/cpp/actors/util/shared_data_rope_backend.h>
 
 namespace NKikimr {
 
@@ -9,7 +10,8 @@ TFragmentedBuffer::TFragmentedBuffer() {
 
 void TFragmentedBuffer::Insert(i32 begin, const char* source, i32 bytesToCopy) {
     Y_VERIFY(bytesToCopy);
-    BufferForOffset[begin].AssignNoAlias(source, bytesToCopy);
+    //FIXME(innokentii): can save allocation
+    BufferForOffset[begin] = TRope(MakeIntrusive<TRopeSharedDataBackend>(TSharedData::Copy(source, bytesToCopy)));
 }
 
 
@@ -17,12 +19,12 @@ bool TFragmentedBuffer::IsMonolith() const {
     return (BufferForOffset.size() == 1 && BufferForOffset.begin()->first == 0);
 }
 
-TString TFragmentedBuffer::GetMonolith() {
+TRope TFragmentedBuffer::GetMonolith() {
     Y_VERIFY(IsMonolith());
     return BufferForOffset.begin()->second;
 }
 
-void TFragmentedBuffer::SetMonolith(TString &data) {
+void TFragmentedBuffer::SetMonolith(TRope &data) {
     Y_VERIFY(data);
     BufferForOffset.clear();
     BufferForOffset.emplace(0, data);
@@ -64,7 +66,7 @@ void TFragmentedBuffer::Write(i32 begin, const char* buffer, i32 size) {
             Y_VERIFY(it->first + i32(it->second.size()) > offset);
             i32 bytesToNext = it->first + it->second.size() - offset;
             i32 bytesToInsert = Min(bytesToCopy, bytesToNext);
-            char *destination = const_cast<char*>(it->second.data()) + offset - it->first;
+            char *destination = it->second.UnsafeGetContiguousSpanMut().data() + offset - it->first;
             memcpy(destination, source, bytesToInsert);
             source += bytesToInsert;
             offset += bytesToInsert;
@@ -97,7 +99,7 @@ void TFragmentedBuffer::Read(i32 begin, char* buffer, i32 size) const {
         Y_VERIFY(it->first + i32(it->second.size()) > offset);
         i32 bytesToNext = it->first + it->second.size() - offset;
         i32 bytesToInsert = Min(bytesToCopy, bytesToNext);
-        const char *source = it->second.data() + offset - it->first;
+        const char *source = const_cast<TRope&>(it->second).GetContiguousSpan().data() + offset - it->first;
         memcpy(destination, source, bytesToInsert);
         destination += bytesToInsert;
         offset += bytesToInsert;
@@ -125,7 +127,7 @@ std::pair<const char*, i32> TFragmentedBuffer::Get(i32 begin) const {
     --it;
     const i32 offset = begin - it->first;
     Y_VERIFY(offset >= 0 && (size_t)offset < it->second.size());
-    return std::make_pair(it->second.data() + offset, it->second.size() - offset);
+    return std::make_pair(const_cast<TRope&>(it->second).GetContiguousSpan().data() + offset, it->second.size() - offset);
 }
 
 void TFragmentedBuffer::CopyFrom(const TFragmentedBuffer& from, const TIntervalSet<i32>& range) {
diff --git a/ydb/core/util/fragmented_buffer.h b/ydb/core/util/fragmented_buffer.h
index 0e7ce9f8425..65088aa6b5e 100644
--- a/ydb/core/util/fragmented_buffer.h
+++ b/ydb/core/util/fragmented_buffer.h
@@ -1,21 +1,22 @@
 #pragma once
 #include "defs.h"
 
+#include <library/cpp/actors/util/rope.h>
 #include <util/generic/map.h>
 #include "interval_set.h"
 
 namespace NKikimr {
 
 class TFragmentedBuffer {
-    TMap<i32, TString> BufferForOffset;
+    TMap<i32, TRope> BufferForOffset;
     void Insert(i32 begin, const char* source, i32 bytesToCopy);
 
 public:
     TFragmentedBuffer();
 
     bool IsMonolith() const;
-    TString GetMonolith();
-    void SetMonolith(TString &data);
+    TRope GetMonolith();
+    void SetMonolith(TRope &data);
 
     void Write(i32 begin, const char* buffer, i32 size);
     void Read(i32 begin, char* buffer, i32 size) const;
diff --git a/ydb/core/util/fragmented_buffer_ut.cpp b/ydb/core/util/fragmented_buffer_ut.cpp
index 7e7dee86df5..7b9dac72b7d 100644
--- a/ydb/core/util/fragmented_buffer_ut.cpp
+++ b/ydb/core/util/fragmented_buffer_ut.cpp
@@ -130,22 +130,22 @@ Y_UNIT_TEST_SUITE(TFragmentedBufferTest) {
         fb.Read(0, buffer, 3);
         UNIT_ASSERT_VALUES_EQUAL(buffer, data2);
         UNIT_ASSERT_VALUES_EQUAL(fb.IsMonolith(), true);
-        TString res = fb.GetMonolith();
+        TRope res = fb.GetMonolith();
         UNIT_ASSERT_VALUES_EQUAL(res.size(), 3);
-        UNIT_ASSERT_VALUES_EQUAL(memcmp(res.data(), data2, 3), 0);
+        UNIT_ASSERT_VALUES_EQUAL(memcmp(res.GetContiguousSpan().data(), data2, 3), 0);
     }
 
     Y_UNIT_TEST(TestSetMonolith) {
-        TString inData = "123";
+        TRope inData = TString("123");
         TFragmentedBuffer fb;
         fb.SetMonolith(inData);
         UNIT_ASSERT_VALUES_EQUAL(fb.IsMonolith(), true);
-        TString res = fb.GetMonolith();
-        UNIT_ASSERT_VALUES_EQUAL(inData, res);
+        TRope res = fb.GetMonolith();
+        UNIT_ASSERT_VALUES_EQUAL(inData.ConvertToString(), res.ConvertToString());
     }
 
     Y_UNIT_TEST(TestReplaceWithSetMonolith) {
-        TString inData = "123";
+        TRope inData = TString("123");
         const char *data3v2 = "5";
         const char *data4 = "678";
         TFragmentedBuffer fb;
@@ -156,8 +156,8 @@ Y_UNIT_TEST_SUITE(TFragmentedBufferTest) {
         UNIT_ASSERT_VALUES_EQUAL(fb.IsMonolith(), false);
         fb.SetMonolith(inData);
         UNIT_ASSERT_VALUES_EQUAL(fb.IsMonolith(), true);
-        TString res = fb.GetMonolith();
-        UNIT_ASSERT_VALUES_EQUAL(inData, res);
+        TRope res = fb.GetMonolith();
+        UNIT_ASSERT_VALUES_EQUAL(inData.ConvertToString(), res.ConvertToString());
     }
 
     Y_UNIT_TEST(CopyFrom) {
diff --git a/ydb/core/util/lz4_data_generator.h b/ydb/core/util/lz4_data_generator.h
index 04ba9508f5a..dd0ecbecae1 100644
--- a/ydb/core/util/lz4_data_generator.h
+++ b/ydb/core/util/lz4_data_generator.h
@@ -5,13 +5,21 @@
 
 namespace NKikimr {
 
-inline TString GenDataForLZ4(const ui64 size, const ui64 seed = 0) {
-    TString data = TString::Uninitialized(size);
+template <class ResultContainer = TString>
+inline ResultContainer GenDataForLZ4(const ui64 size, const ui64 seed = 0) {
+    ResultContainer data = ResultContainer::Uninitialized(size);
     const ui32 long_step = Max<ui32>(2027, size / 20);
     const ui32 short_step = Min<ui32>(53, long_step / 400);
+    char *buffer = [&]() -> char * {
+        if constexpr(std::is_same<ResultContainer, TString>::value) {
+            return data.Detach();
+        } else {
+            return data.mutable_data();
+        }
+    }();
     for (ui32 i = 0; i < data.size(); ++i) {
         const ui32 j = i + seed;
-        data[i] = 0xff & (j % short_step + j / long_step);
+        buffer[i] = 0xff & (j % short_step + j / long_step);
     }
     return data;
 }