diff --git a/pkg/local_object_storage/writecache/put.go b/pkg/local_object_storage/writecache/put.go
index 7da5c4d3..2fbf5091 100644
--- a/pkg/local_object_storage/writecache/put.go
+++ b/pkg/local_object_storage/writecache/put.go
@@ -2,6 +2,7 @@ package writecache
 
 import (
 	"context"
+	"fmt"
 	"time"
 
 	"git.frostfs.info/TrueCloudLab/frostfs-node/pkg/local_object_storage/blobstor/common"
@@ -59,7 +60,15 @@ func (c *cache) Put(ctx context.Context, prm common.PutPrm) (common.PutRes, erro
 
 // putBig writes object to FSTree and pushes it to the flush workers queue.
 func (c *cache) putBig(ctx context.Context, prm common.PutPrm) error {
-	if !c.hasEnoughSpaceFS() {
+	if prm.RawData == nil { // foolproof: RawData should be marshalled by shard.
+		data, err := prm.Object.Marshal()
+		if err != nil {
+			return fmt.Errorf("cannot marshal object: %w", err)
+		}
+		prm.RawData = data
+	}
+	size := uint64(len(prm.RawData))
+	if !c.hasEnoughSpace(size) {
 		return ErrOutOfSpace
 	}
 
diff --git a/pkg/local_object_storage/writecache/state.go b/pkg/local_object_storage/writecache/state.go
index 44caa260..7a52d367 100644
--- a/pkg/local_object_storage/writecache/state.go
+++ b/pkg/local_object_storage/writecache/state.go
@@ -7,10 +7,6 @@ func (c *cache) estimateCacheSize() (uint64, uint64) {
 	return count, size
 }
 
-func (c *cache) hasEnoughSpaceFS() bool {
-	return c.hasEnoughSpace(c.maxObjectSize)
-}
-
 func (c *cache) hasEnoughSpace(objectSize uint64) bool {
 	count, size := c.estimateCacheSize()
 	if c.maxCacheCount > 0 && count+1 > c.maxCacheCount {