系统升级后，ZFS 数据集不再在重新启动时自动挂载

Question

我有一个 Arch linux ZFS 备份系统，它很长时间没有更新，因为它运行良好，没有理由打扰。但是，在最近升级之后，我的 ZFS 数据集在我重新启动时不再自动挂载。不幸的是，这些服务没有指示任何错误消息，我可以运行

# zfs mount -a

系统启动后没有问题。一些细节：

[root@elephant etc]# uname -a
Linux elephant 4.16.11-1-ARCH #1 SMP PREEMPT Tue May 22 21:40:27 UTC 2018 x86_64 GNU/Linux
[root@elephant etc]# pacman -Q | grep spl
spl-dkms 0.7.9-1
spl-utils 0.7.9-1
[root@elephant etc]# pacman -Q | grep zfs
zfs-dkms 0.7.9-1
zfs-utils 0.7.9-1

root@elephant etc]# zfs get mountpoint backup/www
NAME                              PROPERTY    VALUE                              SOURCE
backup/www  mountpoint  /backup/www  default
[root@elephant etc]# zfs get mountpoint backup/data
NAME                               PROPERTY    VALUE                               SOURCE
backup/data  mountpoint  /backup/data  default
[root@elephant etc]# zfs get mountpoint backup/metadata
NAME             PROPERTY    VALUE             SOURCE
backup/metadata  mountpoint  /backup/metadata  default

请特别注意 zfs-mount 服务似乎非常满意：

[root@elephant ~]# systemctl -l status zfs*
? zfs.target - ZFS startup target
   Loaded: loaded (/usr/lib/systemd/system/zfs.target; enabled; vendor preset: enabled)
   Active: active since Mon 2018-05-28 15:30:18 CDT; 1min 32s ago

May 28 15:30:18 elephant systemd[1]: Reached target ZFS startup target.

? zfs-import-cache.service - Import ZFS pools by cache file
   Loaded: loaded (/usr/lib/systemd/system/zfs-import-cache.service; enabled; vendor preset: enabled)
   Active: active (exited) since Mon 2018-05-28 15:30:18 CDT; 1min 32s ago
  Process: 659 ExecStart=/usr/bin/zpool import -c /etc/zfs/zpool.cache -aN (code=exited, status=0/SUCCESS)
  Process: 656 ExecStartPre=/sbin/modprobe zfs (code=exited, status=0/SUCCESS)
 Main PID: 659 (code=exited, status=0/SUCCESS)

May 28 15:30:12 elephant systemd[1]: Starting Import ZFS pools by cache file...
May 28 15:30:18 elephant systemd[1]: Started Import ZFS pools by cache file.

? zfs-zed.service - ZFS Event Daemon (zed)
   Loaded: loaded (/usr/lib/systemd/system/zfs-zed.service; enabled; vendor preset: enabled)
   Active: active (running) since Mon 2018-05-28 15:30:18 CDT; 1min 32s ago
     Docs: man:zed(8)
 Main PID: 1586 (zed)
    Tasks: 3 (limit: 4915)
   Memory: 5.6M
   CGroup: /system.slice/zfs-zed.service
           ??1586 /usr/bin/zed -F

May 28 15:30:18 elephant systemd[1]: Started ZFS Event Daemon (zed).
May 28 15:30:18 elephant zed[1586]: ZFS Event Daemon 0.7.9-1 (PID 1586)
May 28 15:30:18 elephant zed[1586]: Processing events since eid=0
May 28 15:30:18 elephant zed[1591]: eid=1 class=history_event pool_guid=0x7314E37F1A1C0088
May 28 15:30:18 elephant zed[1593]: eid=2 class=config_sync pool_guid=0x7314E37F1A1C0088
May 28 15:30:18 elephant zed[1595]: eid=3 class=pool_import pool_guid=0x7314E37F1A1C0088
May 28 15:30:18 elephant zed[1618]: eid=5 class=config_sync pool_guid=0x7314E37F1A1C0088

? zfs-mount.service - Mount ZFS filesystems
   Loaded: loaded (/usr/lib/systemd/system/zfs-mount.service; enabled; vendor preset: enabled)
   Active: active (exited) since Mon 2018-05-28 15:30:12 CDT; 1min 38s ago
  Process: 657 ExecStart=/usr/bin/zfs mount -a (code=exited, status=0/SUCCESS)
 Main PID: 657 (code=exited, status=0/SUCCESS)

May 28 15:30:12 elephant systemd[1]: Starting Mount ZFS filesystems...
May 28 15:30:12 elephant systemd[1]: Started Mount ZFS filesystems.
[root@elephant ~]#

然而：

[root@elephant ~]# zfs mount
[root@elephant ~]# 
[root@elephant ~]# zfs mount -a
[root@elephant ~]# zfs mount
backup                          /backup
backup/data  /backup/data
backup/metadata                 /backup/metadata
backup/www  /backup/www

我已经没有时间来处理这个问题了，我只想将所有数据集切换到旧挂载，但我仍然很好奇为什么这适用于 zfs 0.6.x 但不适用于 0.7.9 - - 可能是某种系统不兼容？

Answer 1

事实证明我的问题是我没有启用zfs-import.target。当我第一次使用 ZoL 0.6.x 设置这个系统时，我什至不确定这个单元文件是否存在，但无论如何

systemctl enable zfs-import.target

解决了问题。ZFS 数据集再次在启动时正确安装。