ZFS Extend ZFS mirror volume

C

circus78

Hi,
I am using FreeBSD 11.0-RELEASE-p1.
I have mirrored zpool volume:

Code: 
# zpool status
  pool: zroot
 state: ONLINE
  scan: none requested
config:

        NAME         STATE     READ WRITE CKSUM
        zroot        ONLINE       0     0     0
          mirror-0   ONLINE       0     0     0
            mfid0p3  ONLINE       0     0     0
            mfid1p3  ONLINE       0     0     0

errors: No known data errors

Code: 
# df -h
Filesystem            Size    Used   Avail Capacity  Mounted on
zroot/ROOT/default    1.9T    1.3T    607G    69%    /
devfs                 1.0K    1.0K      0B   100%    /dev
zroot/tmp             607G    128K    607G     0%    /tmp
zroot/usr/home        607G    320K    607G     0%    /usr/home
zroot/usr/ports       607G     96K    607G     0%    /usr/ports
zroot/usr/src         607G     96K    607G     0%    /usr/src
zroot/var/audit       607G     96K    607G     0%    /var/audit
zroot/var/crash       607G     96K    607G     0%    /var/crash
zroot/var/log         607G    800K    607G     0%    /var/log
zroot/var/mail        607G     96K    607G     0%    /var/mail
zroot/var/tmp         607G     96K    607G     0%    /var/tmp
zroot                 607G     96K    607G     0%    /zroot

I need to replace two physical disks with bigger ones (from 2 TB to 4 TB each).
What is the correct way to do this?
Thank you!
 
If you have empty drive bays and connectors, the "best" way to do it is:
Code: 
<attach new drive, comes up as something like mfid1>
<partition it in a similar fashion as the others>
# zpool attach zroot mfid0p3 mfid2p3
<wait for it to resilver>
# zpool detach zroot mfid0p3

Repeat for the other drive.

This converts the 2-way mirror vdev into a 3-way mirror vdev, does the resilver, then converts it back to a 2-way mirror vdev. This way, you never lose redundancy in the vdev.

Once both drives have been replaced, then you may need to tell the pool to use the extra space:
Code: 
# zpool online -e zroot mfid0p3
# zpool online -e zroot mdid1p3
 
Hi phoenix, unfortunately I have no other bays.
Is it possible to do this in a different way (I mean: replacing one physical disk at time)?
Thank you very much
 
circus78 said:
Is it possible to do this in a different way (I mean: replacing one physical disk at time)?
Click to expand...
Yes. I've done this with a 4 disk RAID-Z but a mirror should work the same. Offline one of the drives, physically remove it, replace with bigger. Wait for resilver to complete, repeat for the other drive.

Once both disks have been replaced and synced, use gpart resize to extend the freebsd-zfs partitions.

circus78 said:
I am using FreeBSD 11.0-RELEASE-p1.
Click to expand...
Plan your updates. FreeBSD 11.0 has been End-of-Life since November 2017 and is not supported any more.
 
circus78 said:
Hi phoenix, unfortunately I have no other bays.
Is it possible to do this in a different way (I mean: replacing one physical disk at time)?
Thank you very much
Click to expand...

Code: 
# zpool offline zroot mfid0p3
<remove drive from bay 1>
<insert new drive into bay 1>
<partition new drive same as the others, but with the extra space>
# zpool replace zroot mfid0p3
<wait for it to resilver>

Repeat for the drive in bay 2.

Code: 
# zpool online -e mfid0p3
# zpool online -e mfid1p3

Voila!

Be sure to install the boot code onto the new drives, otherwise you won't be able to boot. :)
 
It might not have been obvious but make sure to copy the partition tables to the new disk before adding it back to the pool. And make sure you're replacing mfid1p3, not mfid1.
 
I know this thread is a bit dated but google sent me here with my issue: After replacing my mirror drives with a pair of larger ones and detahcing the small ones after resilvering, there was no size increase of the pool. The suggested

Code: 
# zpool online -e zpool device1
# zpool online -e zpool device2

also did not work.

What finally did the trick for me was this:

# zpool online -e zpool device1 device2
 
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