What to call ZFS vdev that won't change?
I've got an Ubuntu (13.04) Desktop with ZFS support thanks to the PPA zfs-native/stable.
Everything was working really well. I created a RAID-Z1 pool called inground with the following command:
zpool create inground raidz1 sdb sdc sdd sde sdf
Later, after being unable to access the mount point I had created, I ran zpool status and nearly fell off my chair when I saw 1 unavailable and 2 corrupt vdevs in the pool. After a few deep breaths, I noticed that when I'd recently rebooted the system, I had a USD thumb drive in one of the front ports of my tower. This caused all of the /dev/sd* mappings to change, and everything made sense. I removed the USB drive, rebooted, and all was well.
My question is, how do I prevent this in the future? Is there a different, canonical, identifier I can use to refer to the physical drives when adding them as vdevs to the zpool?
Solution 1:
You're not supposed to use /dev/sdX names for ZFS pools in cases where the SCSI device names can change. See the options under /dev/disk...
[root@Davalan /dev/disk]# cd by-
by-id/ by-path/ by-uuid/
I usually use the /dev/disk/by-id entries for my Linux zpools...
# zpool status
pool: vol1
state: ONLINE
scan: scrub repaired 0 in 1h44m with 0 errors on Sat Jul 6 13:12:06 2013
config:
NAME STATE READ WRITE CKSUM
vol1 ONLINE 0 0 0
mirror-0 ONLINE 0 0 0
scsi-35000c5003af99fa7 ONLINE 0 0 0
scsi-35000cca0153ec2d0 ONLINE 0 0 0
mirror-1 ONLINE 0 0 0
scsi-35000cca01540e340 ONLINE 0 0 0
scsi-35000cca01540e298 ONLINE 0 0 0
cache
ata-STEC_M8IOPS-50_STM000136649 ONLINE 0 0 0
and...
[root@Davalan /dev/disk/by-id]# ls -1
ata-STEC_M8IOPS-50_STM000136649
ata-STEC_M8IOPS-50_STM000136649-part1
ata-STEC_M8IOPS-50_STM000136649-part9
scsi-35000c5003af99fa7
scsi-35000c5003af99fa7-part1
scsi-35000c5003af99fa7-part9
scsi-35000cca0153ec2d0
scsi-35000cca0153ec2d0-part1
scsi-35000cca0153ec2d0-part9
scsi-35000cca01540e298
scsi-35000cca01540e298-part1
scsi-35000cca01540e298-part9
scsi-35000cca01540e340
scsi-35000cca01540e340-part1
scsi-35000cca01540e340-part9
scsi-SATA_STEC_M8IOPS-50_STM000136649
scsi-SATA_STEC_M8IOPS-50_STM000136649-part1
scsi-SATA_STEC_M8IOPS-50_STM000136649-part9
wwn-0x5000a720300411f7
wwn-0x5000a720300411f7-part1
wwn-0x5000a720300411f7-part9
wwn-0x5000c5003af99fa7
wwn-0x5000c5003af99fa7-part1
wwn-0x5000c5003af99fa7-part9
wwn-0x5000cca0153ec2d0
wwn-0x5000cca0153ec2d0-part1
wwn-0x5000cca0153ec2d0-part9
wwn-0x5000cca01540e298
wwn-0x5000cca01540e298-part1
wwn-0x5000cca01540e298-part9
wwn-0x5000cca01540e340
wwn-0x5000cca01540e340-part1
wwn-0x5000cca01540e340-part9
Solution 2:
Good news is you can change the vdev configuration scheme by exporting and re-importing your pool. (from ZFS on Linux docs)
admin@Test-ZFS:~$ sudo zpool status tankz
pool: tankz
state: ONLINE
scan: resilvered 15K in 0h0m with 0 errors on Tue Feb 25 16:36:18 2014
config:
NAME STATE READ WRITE CKSUM
tankz ONLINE 0 0 0
raidz1-0 ONLINE 0 0 0
sdc ONLINE 0 0 0
sde ONLINE 0 0 0
sdd ONLINE 0 0 0
errors: No known data errors
admin@Test-ZFS:~$ sudo zpool export tankz
admin@Test-ZFS:~$ sudo zpool import -d /dev/disk/by-id tankz
admin@Test-ZFS:~$ sudo zpool status tankz
pool: tankz
state: ONLINE
scan: resilvered 15K in 0h0m with 0 errors on Tue Feb 25 16:36:18 2014
config:
NAME STATE READ WRITE CKSUM
tankz ONLINE 0 0 0
raidz1-0 ONLINE 0 0 0
ata-VBOX_HARDDISK_VB3b2901c3-c7700ec9 ONLINE 0 0 0
ata-VBOX_HARDDISK_VB4ad696a7-d3e6b542 ONLINE 0 0 0
ata-VBOX_HARDDISK_VBbed2a908-5ddcaedb ONLINE 0 0 0
errors: No known data errors