How to Create a Mirrored ZFS Storage Pool

If you have an additional disk that is the same size as the disk in the ZFS storage pool that was created during the OpenSolaris installation, you might consider creating a two-disk mirrored ZFS storage pool. A two-disk mirrored pool provides better data protection against a disk failure.

Tip - For general recommendations about ZFS storage pools, go to http://www.solarisinternals.com/wiki/index.php/ZFS_Best_Practices_Guide.

Steps

Start a privileged shell.
```
user@opensolaris:-$ pfexec bash
#
```
In this example, the bash shell is selected. You can choose to use any shell with the pfexec command. If you support multiple versions of the Solaris^TM OS, use the standard su – root command. The su command works on all Solaris versions.

Identify your existing storage pool devices.
For example:

# zpool status
  pool: rpool
 state: ONLINE
 scrub: none requested
config:

        NAME        STATE     READ WRITE CKSUM
        rpool       ONLINE       0     0     0
          c4d0s0    ONLINE       0     0     0

errors: No known data errors

Attach a second disk as a mirror to the existing storage pool device.
For example:
```
# zpool attach rpool c4d0s0 c4d1s0
```

Verify that the device is attached.
For example:

# zpool status
  pool: rpool
 state: ONLINE
 scrub: none requested
config:

        NAME          STATE     READ WRITE CKSUM
        rpool         ONLINE       0     0     0
          mirror      ONLINE       0     0     0
              c4d0s0  ONLINE       0     0     0
              c4d1s0  ONLINE       0     0     0

errors: No known data errors

Apply the boot blocks to the newly attached disk.
For example:

# installgrub /boot/grub/stage1 /boot/grub/stage2 /dev/rdsk/c4d1s0

Confirm that you can boot from the newly attached disk by selecting this disk from the BIOS level.

For more information: