[Doc] fix 3fs doc link problem (#762)

Author: SgtPepperr

doc/en/mooncake-store-preview.md

@@ -469,7 +469,7 @@ After enabling the persistence feature:
 - For each `Get` or `BatchGet` operation, if the corresponding kvcache is not found in the memory pool, the system will attempt to read the file data from DFS and return it to the user.
 
 #### 3FS USRBIO Plugin
-If you need to use 3FS's native API (USRBIO) to achieve high-performance persistent file reads and writes, you can refer to the configuration instructions in this document [3FS USRBIO Plugin](/mooncake-store/src/hf3fs/READMD.md).
+If you need to use 3FS's native API (USRBIO) to achieve high-performance persistent file reads and writes, you can refer to the configuration instructions in this document [3FS USRBIO Plugin](/mooncake-store/src/hf3fs/README.md).
 
 ## Mooncake Store Python API
 

doc/zh/mooncake-store-preview.md

@@ -472,7 +472,7 @@ struct ReplicateConfig {
 启用持久化功能后，对于每次 `Put`或`BatchPut` 操作，都会发起一次同步的memory pool写入操作和一次异步的DFS持久化操作。之后执行 `Get`或 `BatchGet` 时，如果在memory pool中没有找到对应的kvcache，则会尝试从DFS中读取该文件数据，并返回给用户。
 
 #### 3FS USRBIO 插件
-如需通过3FS原生接口（USRBIO）实现高性能持久化文件读写，请参阅本文档的配置说明。[3FS USRBIO 插件配置](/mooncake-store/src/hf3fs/READMD.md)。
+如需通过3FS原生接口（USRBIO）实现高性能持久化文件读写，请参阅本文档的配置说明。[3FS USRBIO 插件配置](/mooncake-store/src/hf3fs/README.md)。
 
 ## Mooncake Store Python API
 

docs/source/design/mooncake-store-preview.md

@@ -469,7 +469,7 @@ After enabling the persistence feature:
 - For each `Get` or `BatchGet` operation, if the corresponding kvcache is not found in the memory pool, the system will attempt to read the file data from DFS and return it to the user.
 
 #### 3FS USRBIO Plugin
-If you need to use 3FS's native API (USRBIO) to achieve high-performance persistent file reads and writes, you can refer to the configuration instructions in this document [3FS USRBIO Plugin](/mooncake-store/src/hf3fs/READMD.md).
+If you need to use 3FS's native API (USRBIO) to achieve high-performance persistent file reads and writes, you can refer to the configuration instructions in this document [3FS USRBIO Plugin](https://kvcache-ai.github.io/Mooncake/plugin-usage/3FS-USRBIO-Plugin.html).
 
 ## Mooncake Store Python API
 

docs/source/plugin-usage/3FS-USRBIO-Plugin.md

@@ -0,0 +1,43 @@
+# Mooncake HF3FS Plugin
+
+This plugin implements 3FS native API (USRBIO) as a high-performance storage backend for Mooncake.
+
+## Prerequisites
+
+### 1. 3FS Installation
+- Build and install [3FS](https://github.com/deepseek-ai/3FS/)
+- Required library: `libhf3fs_api_shared.so` (Default location: `3FS_PATH/build/src/lib/api`)  
+  → Install to: `/usr/lib/`
+- Required header: `hf3fs_usrbio.h` (Default location: `3FS_PATH/src/lib/api`)  
+  → Install to: `/usr/include/`
+
+### 2. Mooncake Configuration
+- Enable 3FS support during CMake configuration:
+```bash
+
+cmake -DUSE_3FS=ON ...
+```
+
+- Build and install Mooncake as usual.
+
+## Usage
+
+### Basic Operation
+Start master server and specify the 3FS mount point:
+```bash
+
+./build/mooncake-store/src/mooncake_master \
+    --root_fs_dir=/path/to/3fs_mount_point 
+```
+### Important Notes
+1. The specified directory **must** be a 3FS mount point  
+   - If not, the system will automatically fall back to POSIX API
+2. For optimal performance:
+   - Ensure proper permissions on the 3FS mount point
+   - Verify 3FS service is running before execution
+
+### Example
+```bash
+
+ROLE=prefill MOONCAKE_STORAGE_ROOT_DIR=/mnt/3fs python3 ./stress_cluster_benchmark.py
+```