# 消息 ID：ZFS-8000-K4

## ZFS 意图日志读取失败

|  类型  | 错误              |
| :--: | --------------- |
|  严重性 | 严重              |
|  描述  | 无法读取 ZFS 意图日志设备 |
| 自动响应 | 不会采取自动响应        |
|  影响  | 意图日志无法重放        |

## 建议系统管理员采取的操作

由于错误，无法读取 ZFS 意图日志记录。这可能是由于日志设备丢失或损坏，或者池中的某个设备正在经历 I/O 错误。池本身未损坏，但缺少在断电或系统故障前发生的一些池更改。这些更改是应用程序请求同步写入但尚未在池中提交的事务。事务组提交当前每五秒发生一次，因此通常最多丢失五秒内的同步写入。ZFS 本身无法判断丢失的池更改对故障发生时运行的应用程序是否关键，这需要由管理员决定。建议考虑镜像日志设备。首先确定哪个池出现了错误：

```sh
# zpool status -x
  pool: test
 state: FAULTED
status: One or more of the intent logs could not be read.
        Waiting for administrator intervention to fix the faulted pool.
action: Either restore the affected device(s) and run 'zpool online',
        or ignore the intent log records by running 'zpool clear'.
 scrub: none requested
config:

        NAME              STATE     READ WRITE CKSUM
        test              FAULTED      0     0     0  bad intent log
          c3t2d0          ONLINE       0     0     0
        logs              FAULTED      0     0     0  bad intent log
          c5t3d0          UNAVAIL      0     0     0  cannot open
```

有两种方法可以解决此问题。如果从应用程序的角度看，池更改的有效性至关重要，则必须恢复日志设备。确保电源和连接线已连接，并且受影响的设备在线。然后运行 `zpool online`，随后运行 `zpool clear`：

```sh
# zpool online test c5t3d0
# zpool clear test
# zpool status test
  pool: test
 state: ONLINE
 scrub: none requested
config:

        NAME              STATE     READ WRITE CKSUM
        test              ONLINE       0     0     0
          c3t2d0          ONLINE       0     0     0
        logs              ONLINE       0     0     0
          c5t3d0          ONLINE       0     0     0

errors: No known data errors
```

第二种替代操作是忽略无法读取的最近的池变动。为此，运行 `zpool clear`：

```sh
# zpool clear test
# zpool status test
  pool: test
 state: DEGRADED
status: One or more devices could not be opened.  Sufficient replicas exist for
        the pool to continue functioning in a degraded state.
action: Attach the missing device and online it using 'zpool online'.
   see: https://openzfs.github.io/openzfs-docs/msg/ZFS-8000-2Q
 scrub: none requested
config:

        NAME              STATE     READ WRITE CKSUM
        test              DEGRADED     0     0     0
          c3t2d0          ONLINE       0     0     0
        logs              DEGRADED     0     0     0
          c5t3d0          UNAVAIL      0     0     0  cannot open

errors: No known data errors
```

后续的日志记录将不再使用故障的日志设备，而是写入主池。应修复或更换那些发生故障的日志设备。

## 详细信息

消息 ID：`ZFS-8000-K4` 表示日志设备丢失或无法读取。


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