Oracle Solaris ZFS Administration Guide

ProcedureHow to Replace a Disk in the ZFS Root Pool

You might need to replace a disk in the root pool for the following reasons:

In a mirrored root pool configuration, you can attempt a disk replacement without booting from alternate media. You can replace a failed disk by using the zpool replace command. Or, if you have an additional disk, you can use the zpool attach command. See the procedure in this section for an example of attaching an additional disk and detaching a root pool disk.

Some hardware requires that you take a disk offline and unconfigure it before attempting the zpool replace operation to replace a failed disk. For example:

# zpool offline rpool c1t0d0s0
# cfgadm -c unconfigure c1::dsk/c1t0d0
<Physically remove failed disk c1t0d0>
<Physically insert replacement disk c1t0d0>
# cfgadm -c configure c1::dsk/c1t0d0
# zpool replace rpool c1t0d0s0
# zpool online rpool c1t0d0s0
# zpool status rpool
<Let disk resilver before installing the boot blocks>
SPARC# installboot -F zfs /usr/platform/`uname -i`/lib/fs/zfs/bootblk /dev/rdsk/c1t0d0s0
x86# installgrub /boot/grub/stage1 /boot/grub/stage2 /dev/rdsk/c1t9d0s0

On some hardware, you do not have to online or reconfigure the replacement disk after it is inserted.

You must identify the boot device pathnames of the current disk and the new disk so that you can test booting from the replacement disk and also manually boot from the existing disk, if the replacement disk fails. In the example in the following procedure, the path name for current root pool disk (c1t10d0s0) is:


The path name for the replacement boot disk (c1t9d0s0) is:

  1. Physically connect the replacement (or new) disk.

  2. Confirm that the new disk has an SMI label and a slice 0.

    For information about relabeling a disk that is intended for the root pool, see the following site:

  3. Attach the new disk to the root pool.

    For example:

    # zpool attach rpool c1t10d0s0 c1t9d0s0
  4. Confirm the root pool status.

    For example:

    # zpool status rpool
      pool: rpool
     state: ONLINE
    status: One or more devices is currently being resilvered.  The pool will
            continue to function, possibly in a degraded state.
    action: Wait for the resilver to complete.
     scrub: resilver in progress, 25.47% done, 0h4m to go
            NAME           STATE     READ WRITE CKSUM
            rpool          ONLINE       0     0     0
              mirror-0     ONLINE       0     0     0
                c1t10d0s0  ONLINE       0     0     0
                c1t9d0s0   ONLINE       0     0     0
    errors: No known data errors
  5. After the resilvering is completed, apply the boot blocks to the new disk.

    Using syntax similar to the following:

    • SPARC:

      # installboot -F zfs /usr/platform/`uname -i`/lib/fs/zfs/bootblk /dev/rdsk/c1t9d0s0
    • x86:

      # installgrub /boot/grub/stage1 /boot/grub/stage2 /dev/rdsk/c1t9d0s0
  6. Verify that you can boot from the new disk.

    For example, on a SPARC based system, you would use syntax similar to the following:

    ok boot /pci@8,700000/pci@3/scsi@5/sd@9,0
  7. If the system boots from the new disk, detach the old disk.

    For example:

    # zpool detach rpool c1t10d0s0
  8. Set up the system to boot automatically from the new disk, either by using the eeprom command, the setenv command from the SPARC boot PROM, or reconfigure the PC BIOS.