为什么我的 ZFS 池没有在 Linux 上使用 ZFS 扩展？

Question

我在内核 2.6.32-431.11.2.el6.x86_64 下的 linux 上有一个 ZFS zpool，它有一个 vdev。vdev 是一个 SAN 设备。我扩展了 SAN 的大小，尽管 zpool 已autoexpand设置为on，即使在重新启动机器、导出/导入池并使用 之后zpool online -e，我也无法扩展池。我确信 vdev 更大，因为fdisk显示它已从 215GiB 增加到 250GiB。这是我所做的示例：

[root@timestandstill ~]# zpool list
NAME          SIZE  ALLOC   FREE    CAP  DEDUP  HEALTH  ALTROOT
dfbackup      214G   207G  7.49G    96%  1.00x  ONLINE  -
[root@timestandstill ~]# zpool import -d /dev/disk/by-id/
   pool: dfbackup
     id: 12129781223864362535
  state: ONLINE
 action: The pool can be imported using its name or numeric identifier.
 config:

    dfbackup             ONLINE
      virtio-sbs-XLPH83  ONLINE
[root@timestandstill ~]# zpool import -d /dev/disk/by-id/ dfbackup
[root@timestandstill ~]# zpool list
NAME          SIZE  ALLOC   FREE    CAP  DEDUP  HEALTH  ALTROOT
dfbackup      214G   207G  7.49G    96%  1.00x  ONLINE  -
venuebackup   248G   244G  3.87G    98%  1.00x  ONLINE  -
[root@timestandstill ~]# zpool get autoexpand dfbackup
NAME      PROPERTY    VALUE   SOURCE
dfbackup  autoexpand  on      local
[root@timestandstill ~]# zpool set autoexpand=off dfbackup
[root@timestandstill ~]# zpool set autoexpand=on dfbackup
[root@timestandstill ~]# zpool list
NAME          SIZE  ALLOC   FREE    CAP  DEDUP  HEALTH  ALTROOT
dfbackup      214G   207G  7.49G    96%  1.00x  ONLINE  -
venuebackup   248G   244G  3.87G    98%  1.00x  ONLINE  -
[root@timestandstill ~]# zpool status -v dfbackup
  pool: dfbackup
 state: ONLINE
  scan: none requested
config:

    NAME                 STATE     READ WRITE CKSUM
    dfbackup             ONLINE       0     0     0
      virtio-sbs-XLPH83  ONLINE       0     0     0

errors: No known data errors
[root@timestandstill ~]# fdisk /dev/disk/by-id/virtio-sbs-XLPH83

WARNING: GPT (GUID Partition Table) detected on '/dev/disk/by-id/virtio-sbs-XLPH83'! The util fdisk doesn't support GPT. Use GNU Parted.


WARNING: DOS-compatible mode is deprecated. It's strongly recommended to
         switch off the mode (command 'c') and change display units to
         sectors (command 'u').

Command (m for help): p

Disk /dev/disk/by-id/virtio-sbs-XLPH83: 268.4 GB, 268435456000 bytes
256 heads, 63 sectors/track, 32507 cylinders
Units = cylinders of 16128 * 512 = 8257536 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000

                             Device Boot      Start         End      Blocks   Id  System
/dev/disk/by-id/virtio-sbs-XLPH83-part1               1       27957   225443839+  ee  GPT

Command (m for help): q
[root@timestandstill ~]# zpool online -e dfbackup /dev/disk/by-id/virtio-sbs-XLPH83
[root@timestandstill ~]# zpool list
NAME          SIZE  ALLOC   FREE    CAP  DEDUP  HEALTH  ALTROOT
dfbackup      214G   207G  7.49G    96%  1.00x  ONLINE  -
venuebackup   248G   244G  3.87G    98%  1.00x  ONLINE  -
[root@timestandstill ~]# zpool status -v dfbackup
  pool: dfbackup
 state: ONLINE
  scan: none requested
config:

    NAME                 STATE     READ WRITE CKSUM
    dfbackup             ONLINE       0     0     0
      virtio-sbs-XLPH83  ONLINE       0     0     0

errors: No known data errors

我怎样才能扩展这个 zpool？

Answer 1

我在 Ubuntu 16.04 上运行 ZFS，经过多次反复试验，这就是在不重新启动的情况下扩展磁盘和池大小的方法。我的系统托管在 Profitbricks 的云中，并使用 libvirt（而非 SCSI）驱动器。

获取池和设备详细信息：

# zpool status -v
   ...
    NAME        STATE     READ WRITE CKSUM
    pool        ONLINE       0     0     0
      vdb       ONLINE       0     0     0

# zpool list
NAME   SIZE  ALLOC   FREE  EXPANDSZ   FRAG    CAP  DEDUP  HEALTH  ALTROOT
pool  39.8G  27.1G  12.7G         -    49%    68%  1.00x  ONLINE  -

激活自动展开：

# zpool set autoexpand=on pool

现在登录 Profitbricks 控制面板并将磁盘大小从 40GB 增加到 50GB。

通知系统磁盘大小变化和扩展池：

# partprobe
Warning: Not all of the space available to /dev/vdb appears to be used,
you can fix the GPT to use all of the space (an extra 10485760 blocks) or 
continue with the current setting?

# zpool online -e pool vdb

# partprobe

# zpool list
NAME   SIZE  ALLOC   FREE  EXPANDSZ   FRAG    CAP  DEDUP  HEALTH  ALTROOT
pool  49.8G  27.1G  21.7G         -    40%    55%  1.00x  ONLINE  -

我不确定为什么，但有时需要运行partprobe和/或zpool online -e pool vdb两次才能使更改生效。

Answer 2

我在freebsd 论坛上阅读了一篇建议使用的帖子zpool online -e <pool> <vdev>（无需先使 vdev 脱机）

这最终是解决方案，但它要求首先禁用 ZFS 自动扩展：

[root@timestandstill ~]# zpool list
NAME          SIZE  ALLOC   FREE    CAP  DEDUP  HEALTH  ALTROOT
dfbackup      214G   207G  7.49G    96%  1.00x  ONLINE  -
[root@timestandstill ~]# zpool get autoexpand
NAME         PROPERTY    VALUE   SOURCE
dfbackup     autoexpand  on      local
[root@timestandstill ~]# zpool set autoexpand=off dfbackup
[root@timestandstill ~]# zpool online -e dfbackup /dev/disk/by-id/virtio-sbs-XLPH83
[root@timestandstill ~]# zpool list
NAME          SIZE  ALLOC   FREE    CAP  DEDUP  HEALTH  ALTROOT
dfbackup      249G   207G  42.5G    82%  1.00x  ONLINE  -

在 linux 上使用 ZFS（在内核中，不使用 FUSE），需要使用zpool set autoexpand=off后跟zpool online -e才能让 zpool 为我扩展