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ZFS 数据集在重启时消失

tag-icon • tag-icon linux zfs centos7 zfsonlinux
ZFS 数据集在重启时消失


我在 Centos 7 中安装了 ZFS(0.6.5)，还创建了一个 zpool，除了数据集在重启时消失之外，其他一切都运行正常。
我一直在尝试借助各种在线资源和博客来调试这个问题，但无法得到想要的结果。
重启后，当我发出zfs list命令时，我得到了“没有可用的数据集”，并zpool list给出“没有可用的游泳池” 在网上搜索了很多资料后，我终于可以手动导入缓存文件了zpool import -c 缓存文件但我还是得跑zpool set cachefile=/etc/zfs/zpool.cache 池重启之前，以便稍后在重启后导入。

如下所示systemctl status zfs-import-cache，

zfs-import-cache.service - Import ZFS pools by cache file Loaded: loaded (/usr/lib/systemd/system/zfs-import-cache.service; static) Active: inactive (dead)

cat /etc/sysconfig/zfs

# ZoL userland configuration.

# Run `zfs mount -a` during system start?
ZFS_MOUNT='yes'

# Run `zfs unmount -a` during system stop?
ZFS_UNMOUNT='yes'

# Run `zfs share -a` during system start?
# nb: The shareiscsi, sharenfs, and sharesmb dataset properties.
ZFS_SHARE='yes'

# Run `zfs unshare -a` during system stop?
ZFS_UNSHARE='yes'

# Specify specific path(s) to look for device nodes and/or links for the
# pool import(s). See zpool(8) for more information about this variable.
# It supersedes the old USE_DISK_BY_ID which indicated that it would only
# try '/dev/disk/by-id'.
# The old variable will still work in the code, but is deprecated.
#ZPOOL_IMPORT_PATH="/dev/disk/by-vdev:/dev/disk/by-id"

# Should the datasets be mounted verbosely?
# A mount counter will be used when mounting if set to 'yes'.
VERBOSE_MOUNT='no'

# Should we allow overlay mounts?
# This is standard in Linux, but not ZFS which comes from Solaris where this
# is not allowed).
DO_OVERLAY_MOUNTS='no'

# Any additional option to the 'zfs mount' command line?
# Include '-o' for each option wanted.
MOUNT_EXTRA_OPTIONS=""

# Build kernel modules with the --enable-debug switch?
# Only applicable for Debian GNU/Linux {dkms,initramfs}.
ZFS_DKMS_ENABLE_DEBUG='no'

# Build kernel modules with the --enable-debug-dmu-tx switch?
# Only applicable for Debian GNU/Linux {dkms,initramfs}.
ZFS_DKMS_ENABLE_DEBUG_DMU_TX='no'

# Keep debugging symbols in kernel modules?
# Only applicable for Debian GNU/Linux {dkms,initramfs}.
ZFS_DKMS_DISABLE_STRIP='no'

# Wait for this many seconds in the initrd pre_mountroot?
# This delays startup and should be '0' on most systems.
# Only applicable for Debian GNU/Linux {dkms,initramfs}.
ZFS_INITRD_PRE_MOUNTROOT_SLEEP='0'

# Wait for this many seconds in the initrd mountroot?
# This delays startup and should be '0' on most systems. This might help on
# systems which have their ZFS root on a USB disk that takes just a little
# longer to be available
# Only applicable for Debian GNU/Linux {dkms,initramfs}.
ZFS_INITRD_POST_MODPROBE_SLEEP='0'

# List of additional datasets to mount after the root dataset is mounted?
#
# The init script will use the mountpoint specified in the 'mountpoint'
# property value in the dataset to determine where it should be mounted.
#
# This is a space separated list, and will be mounted in the order specified,
# so if one filesystem depends on a previous mountpoint, make sure to put
# them in the right order.
#
# It is not necessary to add filesystems below the root fs here. It is
# taken care of by the initrd script automatically. These are only for
# additional filesystems needed. Such as /opt, /usr/local which is not
# located under the root fs.
# Example: If root FS is 'rpool/ROOT/rootfs', this would make sense.
#ZFS_INITRD_ADDITIONAL_DATASETS="rpool/ROOT/usr rpool/ROOT/var"

# List of pools that should NOT be imported at boot?
# This is a space separated list.
#ZFS_POOL_EXCEPTIONS="test2"

# Optional arguments for the ZFS Event Daemon (ZED).
# See zed(8) for more information on available options.
#ZED_ARGS="-M"

我不确定这是否是一个已知问题，如果是，有没有什么解决方法？也许这是一种在重启后保存数据集的简单方法，最好没有缓存文件的开销。

答案1

请确保已启用 zfs 服务（目标）。该服务用于在启动/关闭时处理池导入/导出。

zfs.target loaded active active ZFS startup target

您永远不必为此而苦恼。如果有机会，请在您的 zfs 发行版上运行更新，因为我知道启动服务在过去的几个版本中有所改进：

[root@zfs2 ~]# rpm -qi zfs
Name        : zfs
Version     : 0.6.5.2
Release     : 1.el7.centos

答案2

好的，所以池在那里，这意味着问题出在你的 zfs.cache 上，它不是持久的，这就是为什么它在你重新启动时会丢失它的配置。我建议你运行：

      zpool import zfsPool 
      zpool list

并检查它是否可用。重新启动服务器并查看它是否恢复，如果没有，则执行相同的步骤并运行：

      zpool scrub

只是为了确保您的泳池等一切正常。

请同时发布以下内容：

      /etc/default/zfs.conf
      /etc/init/zpool-import.conf

或者，如果您正在寻找解决此问题的方法，您可以按如下方式进行设置。

将值从 1 更改为 0：

    /etc/init/zpool-import.conf

并将以下内容添加到您的 /etc/rc.local：

    zfs mount -a

这就成功了。

答案3

我也遇到了重启后 zfs 消失的问题。运行 CentOS 7.3 和 ZFS 0.6.5.9 重新导入后，它才恢复 (zpool import zfspool)，直到下次重启。

这是对我有用的命令（使其在重启后仍然存在）：

systemctl preset zfs-import-cache zfs-import-scan zfs-mount zfs-share zfs-zed zfs.target

（发现于： https://github.com/zfsonlinux/zfs/wiki/RHEL-%26-CentOS）

答案4

在我的案例中，ZFS 无法导入 zpool，因为它位于云持久卷上，而该卷未物理连接到机器。我猜网络卷在启动过程中比预期的要晚一些才可用。

启动后运行systemctl status zfs-import-cache.service出现以下消息：

● zfs-import-cache.service - Import ZFS pools by cache file
     Loaded: loaded (/lib/systemd/system/zfs-import-cache.service; enabled; vendor preset: enabled)
     Active: failed (Result: exit-code) since Tue 2021-09-07 18:37:28 UTC; 3 months 17 days ago
       Docs: man:zpool(8)
    Process: 780 ExecStart=/sbin/zpool import -c /etc/zfs/zpool.cache -aN (code=exited, status=1/FAILURE)
   Main PID: 780 (code=exited, status=1/FAILURE)

Sep 07 18:37:26 ingress-zfs-2 systemd[1]: Starting Import ZFS pools by cache file...
Sep 07 18:37:28 ingress-zfs-2 zpool[780]: cannot import 'data': no such pool or dataset
Sep 07 18:37:28 ingress-zfs-2 zpool[780]:         Destroy and re-create the pool from
Sep 07 18:37:28 ingress-zfs-2 zpool[780]:         a backup source.
Sep 07 18:37:28 ingress-zfs-2 systemd[1]: zfs-import-cache.service: Main process exited, code=exited, status=1/FAILURE
Sep 07 18:37:28 ingress-zfs-2 systemd[1]: zfs-import-cache.service: Failed with result 'exit-code'.
Sep 07 18:37:28 ingress-zfs-2 systemd[1]: Failed to start Import ZFS pools by cache file.

解决方案是修补zfs-import-cache.service服务文件以包含remote-fs.target依赖项：

[Unit]
...
After=remote-fs.target
...

在 Ubuntu 20.04 上，此文件位于：/etc/systemd/system/zfs-import.target.wants/zfs-import-cache.service。

我认为指定After=remote-fs.target相当于_netdev在文件中使用该选项/etc/fstab（参见：https://unix.stackexchange.com/a/226453/78327）。

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