Booting From an Alternate Disk in a Mirrored ZFS Root Pool

You can create a mirrored ZFS root pool when the system is installed, or you can attach a disk to create a mirrored ZFS root pool after installation. Review the following known issues regarding mirrored ZFS root pools:

• CR 6668666 – You must install the boot information on the additionally attached disks by using the installboot or installgrub commands if you want to enable booting on the other disks in the mirror. If you create a mirrored ZFS root pool with the initial installation method, then this step is unnecessary. For example, if c0t1d0s0 was the second disk added to the mirror, then the installboot or installgrub command would be as follows:

  sparc# installboot -F zfs /usr/platform/`uname -i`/lib/fs/zfs/bootblk /dev/rdsk/c0t1d0s0

  x86# installgrub /boot/grub/stage1 /boot/grub/stage2 /dev/rdsk/c0t1d0s0

• You can boot from different devices in a mirrored ZFS root pool. Depending on the hardware configuration, you might need to update the PROM or the BIOS to specify a different boot device.

  For example, you can boot from either disk (c1t0d0s0 or c1t1d0s0) in this pool.

  # 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 c1t0d0s0 ONLINE 0 0 0 c1t1d0s0 ONLINE 0 0 0

  On a SPARC based system, enter the alternate disk at the ok prompt.

  ok boot /pci@7c0/pci@0/pci@1/pci@0,2/LSILogic,sas@2/disk@1

  After the system is rebooted, confirm the active boot device. For example:

  SPARC# prtconf -vp | grep bootpath bootpath: '/pci@7c0/pci@0/pci@1/pci@0,2/LSILogic,sas@2/disk@1,0:a'

  On an x86 based system, use syntax similar to the following:

  x86# prtconf -v|sed -n '/bootpath/,/value/p' name='bootpath' type=string items=1 value='/pci@0,0/pci8086,25f8@4/pci108e,286@0/disk@0,0:a'

• On an x86 based system, select an alternate disk in the mirrored ZFS root pool from the appropriate BIOS menu.