HP-UX System Administrator's Guide: Logical Volume Management (762803-001, March 2014)

4.7.6.3 Replacing a Mirrored Boot Disk
There are two additional operations you must perform when replacing a mirrored boot disk:
1. You must initialize boot information on the replacement disk.
2. If the replacement requires rebooting the system, and the primary boot disk is being replaced,
you must boot from the alternate boot disk.
In this example, the disk to be replaced is at lunpath hardware path 0/1/1/1.0x3.0x0, with
device special files named /dev/disk/disk14 and /dev/rdisk/disk14. The system is an
HP Integrity server, so the physical volume names must specify the HP-UX partition on the boot disk
(/dev/disk/disk14_p2 and /dev/disk/disk14_p2).
1. Save the hardware paths to the disk.
Run the ioscan command and note the hardware paths of the failed disk as follows:
# ioscan –m lun /dev/disk/disk14
Class I Lun H/W Path Driver S/W State H/W Type Health Description
========================================================================
disk 14 64000/0xfa00/0x0 esdisk CLAIMED DEVICE offline HP MSA Vol
0/1/1/1.0x3.0x0
/dev/disk/disk14 /dev/rdisk/disk14
/dev/disk/disk14_p1 /dev/rdisk/disk14_p1
/dev/disk/disk14_p2 /dev/rdisk/disk14_p2
/dev/disk/disk14_p3 /dev/rdisk/disk14_p3
In this example, the LUN instance number is 14, the LUN hardware path is
64000/0xfa00/0x0, and the lunpath hardware path is 0/1/1/1.0x3.0x0.
When the failed disk is replaced, a new LUN instance and LUN hardware path are created.
To identify the disk after it is replaced, you must use the lunpath hardware path
(0/1/1/1.0x3.0x0).
2. Halt LVM access to the disk.
If the disk is not hot-swappable, power off the system to replace it. By shutting down the system,
you halt LVM access to the disk, so you can skip this step.
If the disk is hot-swappable, detach the device using the –a option of the pvchange command:
# pvchange -a N /dev/disk/disk14_p2
NOTE: On an HP 9000 server, the boot disk is not partitioned so the physical volume refers
to the entire disk, not the HP-UX partition. Use the following command:
# pvchange -a N /dev/disk/disk14
3. Replace the disk.
For the hardware details on how to replace the disk, see the hardware administrator’s guide
for the system or disk array.
If the disk is hot-swappable, replace it.
If the disk is not hot-swappable, shut down the system, turn off the power, and replace the
disk. Reboot the system. Two problems can occur:
• If you replaced the disk that you normally boot from, the replacement disk does not contain
the information needed by the boot loader. In this case, interrupt the boot process and
boot from the mirror boot disk, which is configured as the alternate boot path.
• If there are only two disks in the root volume group, the system probably fails its quorum
check as described in “Volume Group Activation Failures” (page 119). It can panic early
in the boot process with the message:
panic: LVM: Configuration failure
In this situation, you must override quorum to boot successfully. Do this by interrupting
the boot process and adding the –lq option to the boot command.
142 Troubleshooting LVM