systemd zfs-import.target and documentation

zfs-import-{cache,scan}.service must complete before any mounting of
filesystems can occur. To simplify this dependency, create a target
that is reached After (in the systemd sense) the pool is imported.

Additionally, recommend that legacy zfs mounts use the option

x-systemd.requires=zfs-import.target

to codify this requirement.

Reviewed-by: Fabian Grünbichler <f.gruenbichler@proxmox.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Giuseppe Di Natale <dinatale2@llnl.gov>
Signed-off-by: Antonio Russo <antonio.e.russo@gmail.com>
Closes #6764
This commit is contained in:
Antonio Russo 2017-10-30 16:18:26 -04:00 committed by Tony Hutter
parent 246e515cf8
commit 1c4f5e7d92
6 changed files with 23 additions and 7 deletions

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@ -7,6 +7,7 @@ systemdunit_DATA = \
zfs-import-scan.service \
zfs-mount.service \
zfs-share.service \
zfs-import.target \
zfs.target
EXTRA_DIST = \
@ -15,6 +16,7 @@ EXTRA_DIST = \
$(top_srcdir)/etc/systemd/system/zfs-import-scan.service.in \
$(top_srcdir)/etc/systemd/system/zfs-mount.service.in \
$(top_srcdir)/etc/systemd/system/zfs-share.service.in \
$(top_srcdir)/etc/systemd/system/zfs-import.target.in \
$(top_srcdir)/etc/systemd/system/zfs.target.in \
$(top_srcdir)/etc/systemd/system/50-zfs.preset.in

View File

@ -6,6 +6,7 @@ After=systemd-udev-settle.service
After=cryptsetup.target
After=systemd-remount-fs.service
Before=dracut-mount.service
Before=zfs-import.target
ConditionPathExists=@sysconfdir@/zfs/zpool.cache
[Service]
@ -15,5 +16,4 @@ ExecStartPre=/sbin/modprobe zfs
ExecStart=@sbindir@/zpool import -c @sysconfdir@/zfs/zpool.cache -aN
[Install]
WantedBy=zfs-mount.service
WantedBy=zfs.target
WantedBy=zfs-import.target

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@ -5,6 +5,7 @@ Requires=systemd-udev-settle.service
After=systemd-udev-settle.service
After=cryptsetup.target
Before=dracut-mount.service
Before=zfs-import.target
ConditionPathExists=!@sysconfdir@/zfs/zpool.cache
[Service]
@ -14,5 +15,4 @@ ExecStartPre=/sbin/modprobe zfs
ExecStart=@sbindir@/zpool import -aN -o cachefile=none
[Install]
WantedBy=zfs-mount.service
WantedBy=zfs.target
WantedBy=zfs-import.target

View File

@ -0,0 +1,6 @@
[Unit]
Description=ZFS pool import target
[Install]
WantedBy=zfs-mount.service
WantedBy=zfs.target

View File

@ -2,8 +2,7 @@
Description=Mount ZFS filesystems
DefaultDependencies=no
After=systemd-udev-settle.service
After=zfs-import-cache.service
After=zfs-import-scan.service
After=zfs-import.target
After=systemd-remount-fs.service
Before=local-fs.target

View File

@ -440,7 +440,16 @@ If needed, ZFS file systems can also be managed with traditional tools
If a file system's mount point is set to
.Sy legacy ,
ZFS makes no attempt to manage the file system, and the administrator is
responsible for mounting and unmounting the file system.
responsible for mounting and unmounting the file system. Because pools must
be imported before a legacy mount can succeed, administrators should ensure
that legacy mounts are only attempted after the zpool import process
finishes at boot time. For example, on machines using systemd, the mount
option
.Pp
.Nm x-systemd.requires=zfs-import.target
.Pp
will ensure that the zfs-import completes before systemd attempts mounting
the filesystem. See systemd.mount(5) for details.
.Ss Deduplication
Deduplication is the process for removing redundant data at the block level,
reducing the total amount of data stored. If a file system has the