In addition to the zpool add command, you can use the zpool attach command to add a new device to an existing mirrored or nonmirrored device.
If you are attaching a disk to create a mirrored root pool, see How to Create a Mirrored Root Pool (Post Installation).
If you are replacing a disk in a ZFS root pool, see How to Replace a Disk in the ZFS Root Pool.
In this example, zeepool is an existing two-way mirror that is converted to a three-way mirror by attaching c2t1d0, the new device, to the existing device, c1t1d0.
# zpool status zeepool pool: zeepool state: ONLINE scrub: none requested config: NAME STATE READ WRITE CKSUM zeepool ONLINE 0 0 0 mirror-0 ONLINE 0 0 0 c0t1d0 ONLINE 0 0 0 c1t1d0 ONLINE 0 0 0 errors: No known data errors # zpool attach zeepool c1t1d0 c2t1d0 # zpool status zeepool pool: zeepool state: ONLINE scrub: resilver completed after 0h0m with 0 errors on Fri Jan 8 12:59:20 2010 config: NAME STATE READ WRITE CKSUM zeepool ONLINE 0 0 0 mirror-0 ONLINE 0 0 0 c0t1d0 ONLINE 0 0 0 c1t1d0 ONLINE 0 0 0 c2t1d0 ONLINE 0 0 0 592K resilvered errors: No known data errors |
If the existing device is part of a three-way mirror, attaching the new device creates a four-way mirror, and so on. Whatever the case, the new device begins to resilver immediately.
In addition, you can convert a nonredundant storage pool to a redundant storage pool by using the zpool attach command. For example:
# zpool create tank c0t1d0 # zpool status tank pool: tank state: ONLINE scrub: none requested config: NAME STATE READ WRITE CKSUM tank ONLINE 0 0 0 c0t1d0 ONLINE 0 0 0 errors: No known data errors # zpool attach tank c0t1d0 c1t1d0 # zpool status tank pool: tank state: ONLINE scrub: resilver completed after 0h0m with 0 errors on Fri Jan 8 14:28:23 2010 config: NAME STATE READ WRITE CKSUM tank ONLINE 0 0 0 mirror-0 ONLINE 0 0 0 c0t1d0 ONLINE 0 0 0 c1t1d0 ONLINE 0 0 0 73.5K resilvered errors: No known data errors |
You can use the zpool detach command to detach a device from a mirrored storage pool. For example:
# zpool detach zeepool c2t1d0 |
However, this operation fails if no other valid replicas of the data exist. For example:
# zpool detach newpool c1t2d0 cannot detach c1t2d0: only applicable to mirror and replacing vdevs |