Add replication configuration documentation for Java client and HDFS client

Hadoop-Compatible-File-System.md

@@ -81,7 +81,36 @@ Both reads and writes are working fine.
        <!-- [direct|publicUrl|filerProxy] -->
        <value>direct</value>
     </property>
+    <property>
+       <name>fs.seaweed.replication</name>
+       <value>002</value>
+    </property>
 </configuration>
+
+# Replication Configuration
+
+SeaweedFS supports configurable replication for data durability. You can set the replication level using the `fs.seaweed.replication` property in `core-site.xml`.
+
+SeaweedFS uses a 3-digit replication string format: (data center)(rack)(volume server) copies.
+
+**Examples:**
+- `000` or empty: Use default replication (usually 1 copy)
+- `001`: 1 additional copy (2 total copies)
+- `002`: 2 additional copies (3 total copies)
+- `010`: 1 data center + 1 rack copy (3 total copies)
+- `020`: 2 rack copies (3 total copies)
+
+If `fs.seaweed.replication` is not set, SeaweedFS will use the HDFS `dfs.replication` parameter and convert it to the SeaweedFS format.
+
+**Configuration:**
+```xml
+<property>
+   <name>fs.seaweed.replication</name>
+   <value>002</value>
+</property>
+```
+
+You can also set replication programmatically when creating files, though this is less common for HDFS-compatible usage.
 ```
 # Deploy the SeaweedFS HDFS client jar
 ```

SeaweedFS-Java-Client.md

@@ -61,6 +61,33 @@ When starting filer, `weed filer -port=8888`, the port 8888 is default http port
   // next, you can use seaweedOutputStream as a normal OutputStream
 ```
 
+## Write File with Replication
+
+You can specify replication level when writing files. SeaweedFS uses a replication string format: a 3-digit string representing (data center)(rack)(volume server) copies.
+
+```
+  FilerClient filerClient = new FilerClient("localhost", 18888);
+  // Create output stream with replication (e.g., "001" = 1 copy, "002" = 2 copies, "010" = 1 data center + 1 rack copy, etc.)
+  SeaweedOutputStream seaweedOutputStream = new SeaweedOutputStream(filerClient, "/test/"+filename, "002");
+  // next, you can use seaweedOutputStream as a normal OutputStream
+```
+
+Or set replication after creation:
+
+```
+  FilerClient filerClient = new FilerClient("localhost", 18888);
+  SeaweedOutputStream seaweedOutputStream = new SeaweedOutputStream(filerClient, "/test/"+filename);
+  seaweedOutputStream.setReplication("002"); // Set 2 copies replication
+  // next, you can use seaweedOutputStream as a normal OutputStream
+```
+
+Common replication values:
+- `"000"` or `""` (empty string): Use default replication (usually 1 copy)
+- `"001"`: 1 additional copy (2 total)
+- `"002"`: 2 additional copies (3 total) 
+- `"010"`: 1 data center + 1 rack copy (3 total)
+- `"020"`: 2 rack copies (3 total)
+
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