ZFS + LUKS not correctly mounted on boot

[grigio]

Hi,
I've a partition LUKS(ZFS) with is correctly decrypted the problem is that it seems the "zfs mount command" is executed before that the LUKS container is decrypted.

Steps

• boot
• zpool status DEGRADED or sometimes it is ONLINE but I get an empty directory
• I run zpool export cpool and zpool import cpool, then it works

Is possible to avoid these additional commands at every reboot? The OS is Ubuntu 12.04.3
Thanks

[grigio]

probably related to #599
I also have to use -f because sometimes I get "pool may be in use from other system"

[behlendorf]

@grigio For now your probably going to need to manually add a delay to postpone the mount until the LUKS container is open and the devices are available.

[grigio]

i imagined, any hint where to add the delay in ubuntu/upstart ?
i tried with rc.local but i have to force the zfs mount

[behlendorf]

For ubuntu you can try increasing the ZFS_INITRD_PRE_MOUNTROOT_SLEEP value in /etc/defaults/zfs. For most people 30 seconds is enough.

[grigio]

@behlendorf I removed my hacks in rc.local and tried it but I alwais get no pools available

zfs-mountall is installed, to see the volume after the boot I've to run:

$ sudo zpool import cpool
cannot mount '/cpool': directory is not empty
$ sudo zpool status
  pool: cpool
 state: ONLINE
  scan: scrub repaired 79K in 0h0m with 0 errors on Sun Jan 12 13:06:21 2014
config:

    NAME          STATE     READ WRITE CKSUM
    cpool         ONLINE       0     0     0
      sda3_crypt  ONLINE       0     0     0

errors: No known data errors

It's weird, i get "cannot mount.." but then it is mounted correctly

[behlendorf]

Are you sure it mounted? It looks like it imported but didn't mount because something was already at the mount point. You might refer to the following for some troubleshooting tips. Sorry, I'm not familiar with getting things working with LUKS.

https://github.com/zfsonlinux/pkg-zfs/wiki/Ubuntu-ZFS-mountall-FAQ-and-troubleshooting

[grigio]

Yes it mounted and the volumes and data are correcly shown inside the directory, I read the LUKS part but it isn't my situation. My root / is LUKS(ext4) and /cpool is LUKS(zfs). The LUKS(zfs) container is correctly unlocked at boot but then somethng goes wrong, sometimes zpool status says ONLINE but it isn't.

My hacky solution is a /etc/rc.local with:

# HACK: zfs crypto mount
zpool export cpool
sleep 1
zpool import cpool -f

exit 0

I've to export (because sometime it is uncorrectly imported) and use the -f @behlendorf do you think I risk to damage the data in this way?

[behlendorf]

@grigio That safe, but it shouldn't be needed either. Is it possible the vdev device name is different after each boot? That would cause some trouble.

[grigio]

No, it's alwais dm-1

[behlendorf]

@grigio I ask because the output from the command above says sda3_crypt

[grigio]

i think it just label generated by luks

[behlendorf]

@grigio As long as it's consistent that's OK. If it's possible that it changes between reboots that could cause your issue.

[behlendorf]

For distributions which use systemd this style of configuration will be better supported in 0.6.4 thanks to commits like 4f6a147, 07a3312, and d94fd5f. For non-systemd systems this will need to be handled in the distribution specific init process.