diff --git a/src/datanode/src/config.rs b/src/datanode/src/config.rs
index ce48456b6496..b36844ee4a4d 100644
--- a/src/datanode/src/config.rs
+++ b/src/datanode/src/config.rs
@@ -37,7 +37,7 @@ use storage::config::{
 };
 use storage::scheduler::SchedulerConfig;
 
-pub const DEFAULT_OBJECT_STORE_CACHE_SIZE: ReadableSize = ReadableSize(256 * readable_size::MIB);
+pub const DEFAULT_OBJECT_STORE_CACHE_SIZE: ReadableSize = ReadableSize::mb(256);
 
 /// Default data home in file storage
 const DEFAULT_DATA_HOME: &str = "/tmp/greptimedb";