I needed to expand a ZFS pool from a single disk to a pair of disks today. To expand my pool named “striped,” I ran zpool with the “add” option, the pool name to add the disk to, and the device to add to the pool:
$ zpool add striped c1d1
Once the disk was added to the pool, it was immediately available for use:
$ zpool status -v
pool: striped state: ONLINE scrub: none requested config: NAME STATE READ WRITE CKSUM striped ONLINE 0 0 0 c1d0 ONLINE 0 0 0 c1d1 ONLINE 0 0 0 errors: No known data errors
I used to think Veritas had the easiest method to expand file systems, but I don’t think that is the case anymore. Now if we can just get Sun to allow us remove devices from a pool, and expand the number of columns in a RAIDZ or RAIDZ2 vdev!