diff --git a/client/src/main/java/com/alibaba/nacos/client/naming/cache/ConcurrentDiskUtil.java b/client/src/main/java/com/alibaba/nacos/client/naming/cache/ConcurrentDiskUtil.java
index 77eb2bad4e7..d227a6edd26 100644
--- a/client/src/main/java/com/alibaba/nacos/client/naming/cache/ConcurrentDiskUtil.java
+++ b/client/src/main/java/com/alibaba/nacos/client/naming/cache/ConcurrentDiskUtil.java
@@ -143,11 +143,12 @@ public static Boolean writeFileContent(File file, String content, String charset
                 }
             } while (null == lock);
             
-            ByteBuffer sendBuffer = ByteBuffer.wrap(content.getBytes(charsetName));
+            byte[] contentBytes = content.getBytes(charsetName);
+            ByteBuffer sendBuffer = ByteBuffer.wrap(contentBytes);
             while (sendBuffer.hasRemaining()) {
                 channel.write(sendBuffer);
             }
-            channel.truncate(content.length());
+            channel.truncate(contentBytes.length);
         } catch (FileNotFoundException e) {
             throw new IOException("file not exist");
         } finally {
diff --git a/client/src/test/java/com/alibaba/nacos/client/naming/cache/DiskCacheTest.java b/client/src/test/java/com/alibaba/nacos/client/naming/cache/DiskCacheTest.java
index 6079e4da13f..6ec35843bf2 100644
--- a/client/src/test/java/com/alibaba/nacos/client/naming/cache/DiskCacheTest.java
+++ b/client/src/test/java/com/alibaba/nacos/client/naming/cache/DiskCacheTest.java
@@ -47,6 +47,7 @@ public void setUp() throws Exception {
         instance.setIp("1.1.1.1");
         instance.setPort(1234);
         instance.setServiceName("testName");
+        instance.addMetadata("chinese", "中文");
         serviceInfo.setHosts(Collections.singletonList(instance));
     }
     
@@ -87,9 +88,10 @@ private void assertHosts(List<Instance> actual, List<Instance> expected) {
     }
     
     private void assertInstance(Instance actual, Instance expected) {
-        assertEquals(actual.getServiceName(), actual.getServiceName());
-        assertEquals(actual.getClusterName(), actual.getClusterName());
-        assertEquals(actual.getIp(), actual.getIp());
-        assertEquals(actual.getPort(), actual.getPort());
+        assertEquals(actual.getServiceName(), expected.getServiceName());
+        assertEquals(actual.getClusterName(), expected.getClusterName());
+        assertEquals(actual.getIp(), expected.getIp());
+        assertEquals(actual.getPort(), expected.getPort());
+        assertEquals(actual.getMetadata(), expected.getMetadata());
     }
 }