diff --git a/cloud/filestore/libs/storage/core/model.cpp b/cloud/filestore/libs/storage/core/model.cpp
index ae0d94d3aef..93c5cad89cd 100644
--- a/cloud/filestore/libs/storage/core/model.cpp
+++ b/cloud/filestore/libs/storage/core/model.cpp
@@ -507,7 +507,12 @@ ui32 ComputeShardCount(
 {
     const double fileStoreSize = blocksCount * blockSize;
 
-    const ui32 shardCount = std::floor(fileStoreSize / shardAllocationUnit);
+    if (fileStoreSize < shardAllocationUnit) {
+        // No need in using sharding for small enough filesystems
+        return 0;
+    }
+
+    const ui32 shardCount = std::ceil(fileStoreSize / shardAllocationUnit);
     return Min(shardCount, MaxShardCount);
 }
 
diff --git a/cloud/filestore/libs/storage/core/model_ut.cpp b/cloud/filestore/libs/storage/core/model_ut.cpp
index 171322d69cb..d7dd1a768df 100644
--- a/cloud/filestore/libs/storage/core/model_ut.cpp
+++ b/cloud/filestore/libs/storage/core/model_ut.cpp
@@ -2293,13 +2293,13 @@ Y_UNIT_TEST_SUITE(TModel)
     {
         using namespace ::NCloud::NProto;
         KikimrConfig.SetBlockSize(4_KB);
-        KikimrConfig.SetBlocksCount(4_TB / 4_KB);
 
         // Disable media type override.
         StorageConfig.SetAutomaticShardCreationEnabled(true);
         StorageConfig.SetShardAllocationUnit(4_TB);
         StorageConfig.SetAutomaticallyCreatedShardSize(5_TB);
 
+        KikimrConfig.SetBlocksCount(4_TB / 4_KB);
         auto fs = SetupMultiShardFileStorePerformanceAndChannels(
             StorageConfig,
             KikimrConfig,
@@ -2307,6 +2307,22 @@ Y_UNIT_TEST_SUITE(TModel)
             0);
         UNIT_ASSERT_VALUES_EQUAL(1, fs.ShardConfigs.size());
 
+        KikimrConfig.SetBlocksCount(4_TB / 4_KB + 1);
+        fs = SetupMultiShardFileStorePerformanceAndChannels(
+            StorageConfig,
+            KikimrConfig,
+            ClientPerformanceProfile,
+            0);
+        UNIT_ASSERT_VALUES_EQUAL(2, fs.ShardConfigs.size());
+
+        KikimrConfig.SetBlocksCount(5_TB / 4_KB);
+        fs = SetupMultiShardFileStorePerformanceAndChannels(
+            StorageConfig,
+            KikimrConfig,
+            ClientPerformanceProfile,
+            0);
+        UNIT_ASSERT_VALUES_EQUAL(2, fs.ShardConfigs.size());
+
         KikimrConfig.SetBlocksCount(16_TB / 4_KB);
         fs = SetupMultiShardFileStorePerformanceAndChannels(
             StorageConfig,
diff --git a/cloud/filestore/libs/storage/service/service_ut_sharding.cpp b/cloud/filestore/libs/storage/service/service_ut_sharding.cpp
index dc23fd57d10..a9891469eec 100644
--- a/cloud/filestore/libs/storage/service/service_ut_sharding.cpp
+++ b/cloud/filestore/libs/storage/service/service_ut_sharding.cpp
@@ -3717,6 +3717,9 @@ Y_UNIT_TEST_SUITE(TStorageServiceShardingTest)
 
         service.ResizeFileStore(fsId, (4_GB - 4_KB) / 4_KB);
 
+        expected = TVector<TString>{
+            fsId, fsId + "_s1", fsId + "_s2", fsId + "_s3", fsId + "_s4"
+        };
         listing = service.ListFileStores();
         fsIds = listing->Record.GetFileStores();
         ids = TVector<TString>(fsIds.begin(), fsIds.end());
@@ -3725,9 +3728,6 @@ Y_UNIT_TEST_SUITE(TStorageServiceShardingTest)
 
         service.ResizeFileStore(fsId, 4_GB / 4_KB);
 
-        expected = TVector<TString>{
-            fsId, fsId + "_s1", fsId + "_s2", fsId + "_s3", fsId + "_s4"
-        };
         listing = service.ListFileStores();
         fsIds = listing->Record.GetFileStores();
         ids = TVector<TString>(fsIds.begin(), fsIds.end());