diff --git a/fastdeploy/cache_manager/prefix_cache_manager.py b/fastdeploy/cache_manager/prefix_cache_manager.py
index dd64d7fb712..db559ea4c95 100644
--- a/fastdeploy/cache_manager/prefix_cache_manager.py
+++ b/fastdeploy/cache_manager/prefix_cache_manager.py
@@ -1249,17 +1249,20 @@ def issue_write_back_storage_task(self, task: WriteStorageTask, is_sync=True):
         if self.kvcache_storage_backend is None:
             return
 
-        if len(task.keys) != len(task.gpu_block_ids):
-            err_msg = (
-                f"write_back_storage error: hash_keys({len(task.keys)}) != gpu_block_ids({len(task.gpu_block_ids)})"
-            )
-            logger.error(err_msg)
-            raise ValueError(err_msg)
-
-        self.task_write_back_event[task.task_id] = Event()
-        self.cache_task_queue.put_transfer_task((CacheStatus.GPU2STORAGE, task))
-        if is_sync:
-            self.wait_write_storage_task(task.task_id)
+        assert is_sync, "Only support is_sync=True for now."
+        self._acquire_kvcache_lock()
+        try:
+            if len(task.keys) != len(task.gpu_block_ids):
+                err_msg = f"write_back_storage error: hash_keys({len(task.keys)}) != gpu_block_ids({len(task.gpu_block_ids)})"
+                logger.error(err_msg)
+                raise ValueError(err_msg)
+
+            self.task_write_back_event[task.task_id] = Event()
+            self.cache_task_queue.put_transfer_task((CacheStatus.GPU2STORAGE, task))
+            if is_sync:
+                self.wait_write_storage_task(task.task_id)
+        finally:
+            self._release_kvcache_lock()
 
     def wait_write_storage_task(self, req_id):
         """
@@ -1276,12 +1279,18 @@ def issue_prefetch_storage_task(self, task: ReadStorageTask, is_sync=True):
         if self.kvcache_storage_backend is None:
             return []
 
-        storage_block_ids = []
-        self.task_prefetch_event[task.task_id] = Event()
-        # issue task to cache_transfer_manager
-        self.cache_task_queue.put_transfer_task((CacheStatus.STORAGE2GPU, task))
-        if is_sync:
-            storage_block_ids = self.wait_prefetch_storage_task(task.task_id)
+        assert is_sync, "Only support is_sync=True for now."
+        self._acquire_kvcache_lock()
+
+        try:
+            storage_block_ids = []
+            self.task_prefetch_event[task.task_id] = Event()
+            # issue task to cache_transfer_manager
+            self.cache_task_queue.put_transfer_task((CacheStatus.STORAGE2GPU, task))
+            if is_sync:
+                storage_block_ids = self.wait_prefetch_storage_task(task.task_id)
+        finally:
+            self._release_kvcache_lock()
         return storage_block_ids
 
     def wait_prefetch_storage_task(self, req_id):
diff --git a/fastdeploy/cache_manager/transfer_factory/mooncake_store/mooncake_store.py b/fastdeploy/cache_manager/transfer_factory/mooncake_store/mooncake_store.py
index 13273b11e5a..becbff9b97e 100644
--- a/fastdeploy/cache_manager/transfer_factory/mooncake_store/mooncake_store.py
+++ b/fastdeploy/cache_manager/transfer_factory/mooncake_store/mooncake_store.py
@@ -150,13 +150,12 @@ def __init__(self, tp_rank=None):
 
     def warmup(self):
         warmup_key = "fastdeploy_mooncake_store_warmup_key" + str(uuid.uuid4())
-        warmup_value = bytes(1 * 1024 * 1024)  # 1 MB
+        warmup_value = bytes(4 * 1024)  # 4 kb
         rc = self.store.put(warmup_key, warmup_value)
         assert rc == 0, f"Failed to put warmup key, key:{warmup_key}, error code: {rc}"
         rc = self.store.is_exist(warmup_key)
         assert rc == 1, f"Failed to check existence, key:{warmup_key}, error code: {rc}"
         self.store.get(warmup_key)
-        self.store.remove(warmup_key)
 
     def register_buffer(self, buffer_ptr, buffer_size) -> None:
         try: