Have you ever run out of disk space on your production server? Do you cringe at the downtime required to bring filesystems offline, backup, create bigger filesystems, and restore, all the while typing with crossed fingers? Do you dread deciding the disk layout for your new server? You do not need to panic! ZFS has you covered. In one simple command, you can add space to a ZFS pool without taking it offline.
Given a ZFS pool techrx and an unused disk denoted by c1t0d0, you can add the disk to the pool (A non-mirrored pool — That is another tech-recipe.) with this command:
zpool add techrx c1t0d0
Before, the output of zfs list showed the following:
NAME USED AVAIL REFER MOUNTPOINT
techrx 295K 19.2G 25.5K /techrx
After the zpool command, the same command shows the following:
NAME USED AVAIL REFER MOUNTPOINT
techrx 296K 38.4G 25.5K /techrx
It is worth pointing out again that this command works on a live, mounted filesystem. All of the filesystems in the techrx pool benefit from this increase in space (unless they have a quota).
