> For the complete documentation index, see [llms.txt](https://documentation.alluxio.io/os-cn/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://documentation.alluxio.io/os-cn/operation/admin-cli.md).

# 管理员命令行接口

Alluxio的管理员命令行接口为管理员提供了管理Alluxio文件系统的操作。 您可以调用以下命令行来获取所有子命令：

```console
$ ./bin/alluxio fsadmin
Usage: alluxio fsadmin [generic options]
       [report]
       [ufs --mode <noAccess/readOnly/readWrite> <ufsPath>]
       ...
```

以UFS URI作为参数的`fsadmin ufs`子命令，参数应该是像`hdfs://<name-service>/`这样的根UFS URI，而不是`hdfs://<name-service>/<folder>`。

## 操作列表

| 操作     | 语法                                                  | 描述                                                                         |
| ------ | --------------------------------------------------- | -------------------------------------------------------------------------- |
| backup | backup \[directory] \[--local]                      | Back up all Alluxio metadata to the backup directory configured on master. |
| doctor | doctor \[category]                                  | Show Alluxio errors and warnings.                                          |
| report | report \[category] \[category args]                 | Report Alluxio running cluster information.                                |
| ufs    | ufs --mode \<noAccess/readOnly/readWrite> "ufsPath" | Update attributes for a mounted under storage system.                      |

## 示例用例

### backup(备份)

`backup`命令创建Alluxio元数据的备份

备份到默认备份文件夹（由`alluxio.master.backup.directory`）配置

```
./bin/alluxio fsadmin backup
Successfully backed up journal to hdfs://mycluster/opt/alluxio/backups/alluxio-backup-2018-5-29-1527644810.gz
```

备份到下存储中的特定目录。

```
./bin/alluxio fsadmin backup /alluxio/special_backups
Successfully backed up journal to hdfs://mycluster/opt/alluxio/backups/alluxio-backup-2018-5-29-1527644810.gz
```

备份到主主机的本地文件系统的特定目录。

```
./bin/alluxio fsadmin backup /opt/alluxio/backups/ --local
Successfully backed up journal to file:///opt/alluxio/backups/alluxio-backup-2018-5-29-1527644810.gz on master Master2
```

### doctor

`doctor`命令显示Alluxio错误和警告。

```console
# shows server-side configuration errors and warnings
$ ./bin/alluxio fsadmin doctor configuration
```

### report

`report`命令提供了Alluxio运行中的集群信息。

```console
# Report cluster summary
$ ./bin/alluxio fsadmin report

# Report worker capacity information
$ ./bin/alluxio fsadmin report capacity

# Report runtime configuration information 
$ ./bin/alluxio fsadmin report configuration

# Report metrics information
$ ./bin/alluxio fsadmin report metrics

# Report under file system information
$ ./bin/alluxio fsadmin report ufs
```

使用 `-h` 选项来获得更多信息。

### ufs

`ufs`命令提供了选项来更新挂载的底层存储的属性。`mode`选项可用于将底层存储设置为维护模式。目前某些操作可能会受到限制。

例如，一个底层存储可以设为`readOnly`模式来禁止写入操作。 Alluxio将不会对底层存储尝试任何写入操作。

```console
$ ./bin/alluxio fsadmin ufs --mode readOnly hdfs://ns
```

`fsadmin ufs`命令接受一个UFS URI作为参数。该参数需要是一个 UFS URI的根，类似`hdfs://<name-service>/`，而非`hdfs://<name-service>/<folder>`。