Ubuntu
grub2 package

GRUB fails to install during ZFS replace resilvers

Bug #1639209 reported by Richard Laager on 2016-11-04

This bug affects 1 person

Affects		Status	Importance	Assigned to	Milestone
	grub2 (Ubuntu)	New	Undecided	Unassigned

Bug Description

Replace a drive in a pool.
zpool replace grape1 sdg1 sdf1

Note that this creates a replacing-0 line in the zpool status output:

root@grape:~# zpool status
  pool: grape1
state: ONLINE
status: One or more devices is currently being resilvered. The pool will
continue to function, possibly in a degraded state.
action: Wait for the resilver to complete.
  scan: resilver in progress since Fri Nov 4 04:58:55 2016
    37.4G scanned out of 4.06T at 17.6M/s, 66h42m to go
    5.26G resilvered, 0.90% done
config:

NAME STATE READ WRITE CKSUM
grape1 ONLINE 0 0 0
   raidz3-0 ONLINE 0 0 0
     replacing-0 ONLINE 0 0 0
       sdg1 ONLINE 0 0 0
       sdf1 ONLINE 0 0 0 (resilvering)
     sdd1 ONLINE 0 0 0
     sdc1 ONLINE 0 0 0
     sdb1 ONLINE 0 0 0
     sdh1 ONLINE 0 0 0
     sde1 ONLINE 0 0 0
     sda1 ONLINE 0 0 0

errors: No known data errors

Then try to install GRUB to that drive:

root@grape:~# grub-install /dev/sdf
Installing for i386-pc platform.
grub-install: error: failed to get canonical path of `/dev/replacing-0'.

The attached patch fixes this.

Unfortunately, then I get this:

root@grape:~# grub-install /dev/sdf
Installing for i386-pc platform.
grub-install: error: unknown filesystem.

Tags:

Revision history for this message

Richard Laager (rlaager) wrote on 2016-11-04:

zfs-ignore-replacing.patch Edit (343 bytes, text/plain)

Revision history for this message

Ubuntu Foundations Team Bug Bot (crichton) wrote on 2016-11-04:

The attachment "zfs-ignore-replacing.patch" seems to be a patch. If it isn't, please remove the "patch" flag from the attachment, remove the "patch" tag, and if you are a member of the ~ubuntu-reviewers, unsubscribe the team.

[This is an automated message performed by a Launchpad user owned by ~brian-murray, for any issues please contact him.]

Revision history for this message

Richard Laager (rlaager) wrote on 2016-11-05:

Once the resilver completed, I was able to grub-install successfully. Looking at the grub-install debug output, it seems that GRUB looks primarily at the first device. I have a hunch that my patch would fix the case where the first device is not the one being resilvered. But we still need to fix the case where the first device is being resilvered.

Revision history for this message

Richard Laager (rlaager) wrote on 2016-11-05: