[Docs] Supply BE config docs of setting and examples

docs/en/administrator-guide/config/be_config.md

@@ -34,10 +34,47 @@ This document mainly introduces the relevant configuration items of BE.
 (TODO)
 
 ## Set configuration items
-(TODO)
+
+There are two ways to configure BE configuration items:
+
+1. Static configuration
+
+         Add and set configuration items in the `conf/be.conf` file. The configuration items in `be.conf` will be read when BE starts. Configuration items not in `be.conf` will use default values.
+
+2. Dynamic configuration
+
+         After BE starts, the configuration items can be dynamically set with the following commands.
+
+         ```curl -X POST http://{be_ip}:{be_http_port}/api/update_config?{key}={value}'```
+
+         **Configuration items modified in this way will become invalid after the BE process restarts. **
 
 ## Examples
-(TODO)
+
+1. Modify `max_compaction_concurrency` statically
+
+         By adding in the `be.conf` file:
+
+         ```max_compaction_concurrency=5```
+
+         Then restart the BE process to take effect the configuration.
+
+2. Modify `streaming_load_max_mb` dynamically
+
+         After BE starts, the configuration item `streaming_load_max_mb` is dynamically set by the following command:
+
+         ```curl -X POST http://{be_ip}:{be_http_port}/api/update_config?streaming_load_max_mb=1024```
+
+         The return value is as follows, indicating that the setting is successful.
+
+         ```
+         {
+             "status": "OK",
+             "msg": ""
+         }
+         ```
+
+         **The configuration will be invalid after BE restarted. **
 
 ## Configurations
 
@@ -385,6 +422,11 @@ Indicates how many tablets in this data directory failed to load. At the same ti
 
 ### `min_compaction_failure_interval_sec`
 
+* Type: int32
+* Description: During the cumulative compaction process, when the selected tablet fails to be merged successfully, it will wait for a period of time before it may be selected again. The waiting period is the value of this configuration.
+* Default value: 600
+* Unit: seconds
+
 ### `min_cumulative_compaction_num_singleton_deltas`
 
 ### `min_file_descriptor_number`

docs/zh-CN/administrator-guide/config/be_config.md

@@ -34,10 +34,47 @@ under the License.
 （TODO）
 
 ## 设置配置项
-（TODO）
+
+BE 的配置项有两种方式进行配置：
+
+1. 静态配置
+
+	在 `conf/be.conf` 文件中添加和设置配置项。`be.conf` 中的配置项会在 BE 进行启动时被读取。没有在 `be.conf` 中的配置项将使用默认值。
+
+2. 动态配置
+
+	BE 启动后，可以通过一下命令动态设置配置项。
+
+	```curl -X POST http://{be_ip}:{be_http_port}/api/update_config?{key}={value}'```
+
+	**通过该方式修改的配置项将在 BE 进程重启后失效。**
 
 ## 应用举例
-（TODO）
+
+1. 静态方式修改 `max_compaction_concurrency`
+
+	通过在 `be.conf` 文件中添加：
+
+	```max_compaction_concurrency=5```
+
+	之后重启 BE 进程以生效该配置。
+
+2. 动态方式修改 `streaming_load_max_mb`
+
+	BE 启动后，通过下面命令动态设置配置项 `streaming_load_max_mb`:
+
+	```curl -X POST http://{be_ip}:{be_http_port}/api/update_config?streaming_load_max_mb=1024```
+
+	返回值如下，则说明设置成功。
+
+	```
+	{
+	    "status": "OK",
+	    "msg": ""
+	}
+	```
+
+	**BE 重启后该配置将失效。**
 
 ## 配置项列表
 
@@ -384,6 +421,11 @@ load tablets from header failed, failed tablets size: xxx, path=xxx
 
 ### `min_compaction_failure_interval_sec`
 
+* 类型：int32
+* 描述：在 cumulative compaction 过程中，当选中的 tablet 没能成功的进行版本合并，则会等待一段时间后才会再次有可能被选中。等待的这段时间就是这个配置的值。
+* 默认值：600
+* 单位：秒
+
 ### `min_cumulative_compaction_num_singleton_deltas`
 
 ### `min_file_descriptor_number`