ZFS 无限重同步

Question

我在 Debian 上有一个大型（> 100TB）ZFS (FUSE) 池，它丢失了两个驱动器。由于驱动器出现故障，我用备件替换它们，直到我可以安排停机并物理更换坏磁盘。

当我关闭系统并更换驱动器时，池开始按预期重新同步，但是当它完成大约 80% 时（这通常需要大约 100 小时），它再次重新启动。

我不确定一次更换两个驱动器是否会造成竞争条件，或者由于池的大小，重新同步器花费的时间太长以至于其他系统进程正在中断它并导致它重新启动，但是在“zpool status”的结果或指向问题的系统日志。

从那以后，我修改了我如何布置这些池以提高重新同步性能，但对让此系统重新投入生产的任何线索或建议表示赞赏。

zpool 状态输出（自上次检查以来，这些错误是新的）：

  pool: pod
 state: ONLINE
status: One or more devices has experienced an error resulting in data
    corruption.  Applications may be affected.
action: Restore the file in question if possible.  Otherwise restore the
    entire pool from backup.
   see: http://www.sun.com/msg/ZFS-8000-8A
 scrub: resilver in progress for 85h47m, 62.41% done, 51h40m to go
config:

    NAME                                                 STATE     READ WRITE CKSUM
    pod                                                  ONLINE       0     0 2.79K
      raidz1-0                                           ONLINE       0     0 5.59K
        disk/by-id/wwn-0x5000c5003f216f9a                ONLINE       0     0     0
        disk/by-id/scsi-SATA_ST3000DM001-9YN_Z1F0CWPK    ONLINE       0     0     0
        disk/by-id/scsi-SATA_ST3000DM001-9YN_Z1F0BQAM    ONLINE       0     0     0
        disk/by-id/scsi-SATA_ST3000DM001-9YN_Z1F0BPVD    ONLINE       0     0     0
        disk/by-id/scsi-SATA_ST3000DM001-9YN_Z1F0BQ2Y    ONLINE       0     0     0
        disk/by-id/scsi-SATA_ST3000DM001-9YN_Z1F0CVA3    ONLINE       0     0     0
        disk/by-id/scsi-SATA_ST3000DM001-9YN_Z1F0BQHC    ONLINE       0     0     0
        disk/by-id/scsi-SATA_ST3000DM001-9YN_Z1F0BPWW    ONLINE       0     0     0
        disk/by-id/scsi-SATA_ST3000DM001-9YN_Z1F09X3Z    ONLINE       0     0     0
        disk/by-id/scsi-SATA_ST3000DM001-9YN_Z1F0BQ87    ONLINE       0     0     0
        spare-10                                         ONLINE       0     0     0
          disk/by-id/scsi-SATA_ST3000DM001-1CH_W1F20T1K  ONLINE       0     0     0  1.45T resilvered
          disk/by-id/scsi-SATA_ST3000DM001-9YN_Z1F09BJN  ONLINE       0     0     0  1.45T resilvered
        disk/by-id/scsi-SATA_ST3000DM001-9YN_Z1F0BQG7    ONLINE       0     0     0
        disk/by-id/scsi-SATA_ST3000DM001-9YN_Z1F0BQKM    ONLINE       0     0     0
        disk/by-id/scsi-SATA_ST3000DM001-9YN_Z1F0BQEH    ONLINE       0     0     0
        disk/by-id/scsi-SATA_ST3000DM001-9YN_Z1F09C7Y    ONLINE       0     0     0
        disk/by-id/scsi-SATA_ST3000DM001-9YN_Z1F0CWRF    ONLINE       0     0     0
        disk/by-id/scsi-SATA_ST3000DM001-9YN_Z1F0BQ7Y    ONLINE       0     0     0
        disk/by-id/scsi-SATA_ST3000DM001-9YN_Z1F0C7LN    ONLINE       0     0     0
        disk/by-id/scsi-SATA_ST3000DM001-9YN_Z1F0BQAD    ONLINE       0     0     0
        disk/by-id/scsi-SATA_ST3000DM001-9YN_Z1F0CBRC    ONLINE       0     0     0
        disk/by-id/scsi-SATA_ST3000DM001-9YN_Z1F0BPZM    ONLINE       0     0     0
        disk/by-id/scsi-SATA_ST3000DM001-9YN_Z1F0BPT9    ONLINE       0     0     0
        disk/by-id/scsi-SATA_ST3000DM001-9YN_Z1F0BQ0M    ONLINE       0     0     0
        spare-23                                         ONLINE       0     0     0
          disk/by-id/scsi-SATA_ST3000DM001-1CH_W1F226B4  ONLINE       0     0     0  1.45T resilvered
          disk/by-id/scsi-SATA_ST3000DM001-9YN_Z1F0CCMV  ONLINE       0     0     0
        disk/by-id/scsi-SATA_ST3000DM001-9YN_Z1F0D6NL    ONLINE       0     0     0
        disk/by-id/scsi-SATA_ST3000DM001-9YN_Z1F0CWA1    ONLINE       0     0     0
        disk/by-id/scsi-SATA_ST3000DM001-9YN_Z1F0CVL6    ONLINE       0     0     0
        disk/by-id/scsi-SATA_ST3000DM001-9YN_Z1F0D6TT    ONLINE       0     0     0
        disk/by-id/scsi-SATA_ST3000DM001-9YN_Z1F0BPVX    ONLINE       0     0     0
        disk/by-id/scsi-SATA_ST3000DM001-9YN_Z1F09BGJ    ONLINE       0     0     0
        disk/by-id/scsi-SATA_ST3000DM001-9YN_Z1F0C9YA    ONLINE       0     0     0
        disk/by-id/scsi-SATA_ST3000DM001-9YN_Z1F09B50    ONLINE       0     0     0
        disk/by-id/scsi-SATA_ST3000DM001-9YN_Z1F0AZ20    ONLINE       0     0     0
        disk/by-id/scsi-SATA_ST3000DM001-9YN_Z1F0BKJW    ONLINE       0     0     0
        disk/by-id/scsi-SATA_ST3000DM001-9YN_Z1F095Y2    ONLINE       0     0     0
        disk/by-id/scsi-SATA_ST3000DM001-9YN_Z1F08YLD    ONLINE       0     0     0
        disk/by-id/scsi-SATA_ST3000DM001-9YN_Z1F0BQGQ    ONLINE       0     0     0
        disk/by-id/scsi-SATA_ST3000DM001-9YN_Z1F0B2YJ    ONLINE       0     0    39  512 resilvered
        disk/by-id/scsi-SATA_ST3000DM001-9YN_Z1F0BQBY    ONLINE       0     0     0
        disk/by-id/scsi-SATA_ST3000DM001-9YN_Z1F0C9WZ    ONLINE       0     0     0  67.3M resilvered
        disk/by-id/scsi-SATA_ST3000DM001-9YN_Z1F0BQGE    ONLINE       0     0     0
        disk/by-id/scsi-SATA_ST3000DM001-9YN_Z1F0BQ5C    ONLINE       0     0     0
        disk/by-id/scsi-SATA_ST3000DM001-9YN_Z1F0CWWH    ONLINE       0     0     0
    spares
      disk/by-id/scsi-SATA_ST3000DM001-9YN_Z1F0CCMV      INUSE     currently in use
      disk/by-id/scsi-SATA_ST3000DM001-9YN_Z1F09BJN      INUSE     currently in use

errors: 572 data errors, use '-v' for a list

Answer 1

恭喜你哦。您偶然发现了关于 ZFS 的一个更好的事情，但也犯了配置错误。

首先，由于您使用的是 raidz1，因此您只有一个磁盘的奇偶校验数据。但是，您有两个驱动器同时发生故障。这里唯一可能的结果是数据丢失。再多的重新同步也无法解决这个问题。

您的备件在此处为您提供了一些帮助，并使您免于完全灾难性的故障。我将在这里冒昧地说两个发生故障的驱动器没有同时发生故障，第一个备用驱动器仅在第二个驱动器发生故障之前部分重新同步。

这似乎很难遵循。这是一张图片：

This is actually a good thing because if this were a traditional RAID array, your entire array would have simply gone offline as soon as the second drive failed and you would have NO chance of an in-place recovery. But because this is ZFS, it can still run using the pieces it has and simply returns block or file level errors for the pieces it doesn't.

Here is how you fix it: Short-term, get a list of damaged files from zpool status -v and copy those files from backup to their original locations. Or delete the files. This will allow the resilver to resume and complete.

Here is your configuration sin: you have way too many drives in a raidz group.

长期：您需要重新配置驱动器。更合适的配置是在raidz1 中将驱动器分成5 个左右的小组。ZFS 将自动跨这些小组进行条带化。这显着减少了驱动器故障时的重新同步时间，因为只需要 5 个驱动器而不是所有驱动器都需要参与。执行此操作的命令类似于：

zpool create tank raidz da0 da1 da2 da3 da4 \
                  raidz da5 da6 da7 da8 da9 \
                  raidz da10 da11 da12 da13 da14 \
                  spare da15 spare da16