Is there a way to convert a 2 disk raid-z file system to a mirror without
backing up the data and restoring?
We have this:
bash-3.00# zpool status
pool: archives
state: ONLINE
scrub: none requested
config:
NAME STATE READ WRITE CKSUM
archives ONLINE 0 0 0
raidz1 ONLINE 0 0 0
c1t2d0 ONLINE 0 0 0
c1t3d0 ONLINE 0 0 0
... and what I would like to be able to do is to:
- remove c1t3d0 from the raidz, leaving it in degraded mode momentarily.
- Create a new pool with the single disk c1t3d0
- copy the data from the current pool to the new pool
- destroy the current pool
- attach c1t2d0 to the new pool, creating a mirror
I can''t seem to find any way to remove c1t3d0 from the raidz pool. The
best I can do is "offline" it, which proves the pool can still run
without the disk, but I can''t seem to free the disk.
Any ideas?
Brian
This message posted from opensolaris.org
Hello Brian, On Fri, Sep 14, 2007 at 11:45:27AM -0700, Brian King wrote:> Is there a way to convert a 2 disk raid-z file system to a mirror without backing up the data and restoring? >Currently there isn''t a way to do this without having some additional buffer disk space available. What you can do is attach some vdev to your current raidz. This will create a mirror. After the resync, detach your raidz, do whatever you want to do, like attach the first disk of your raidz. Now you may either detach your buffer-vdev or attach the second disk from your former raidz. The order doesn''t really matter that much. And you have moved your pool around without backing up the data. You have to watch the exact sizes of the disks/vdev though, since the space in a mirror only occupies the size of the smallest vdev and grows with the size of the smallest vdev. Last weekend, I had to move a pool around and attached an external USB-drive with a disk considerably larger than my zpool. So I created a zpool on the disk and used a zvol as the buffer-vdev. HTH, Patrick
Thanks for your idea. That would be useful if we had the extra space. After playing with a test zpool for a bit, I found that this also works, but you have to make the pool unavailable for a while. I''m just posting it in case it helps someone else. - destroy the raidz pool - reuse one of the disks in a new pool - recover the raidz pool in degraded mode - copy the files to the new pool - destroy the original pool again - attach the final disk to the new pool as a mirror e.g. # mkfile 64m a # mkfile 64m b # zpool create raidz temp `pwd`/a `pwd`/b # echo test >/temp/test # cat /temp/test test # zpool destroy temp # zpool create -f temp2 `pwd`/b # note -f to force to overwrite 1/2 of old pool # zpool import -d `pwd` temp # zpool list NAME SIZE USED AVAIL CAP HEALTH ALTROOT temp 119M 453K 119M 0% DEGRADED - temp2 59.5M 83.5K 59.4M 0% ONLINE - # cat /temp/test test # mv /temp/* /temp # zpool destroy temp # zpool attach temp2 `pwd`/b `pwd`/a I would recommend Patrick''s suggestion or backing up and restoring (if those options are available) though. This way is riskier since there are times when your data is unavailable and depending on a recover to bring it back. This message posted from opensolaris.org
Update to this. Before destroying the original pool the first time, offline the disk you plan on re-using in the new pool. Otherwise when you destroy the original pool for the second time it causes issues with the new pool. In fact, if you attempt to destroy the new pool immediately after destroying the original pool, the system will panic. This message posted from opensolaris.org