Managing Systems and Workgroups: A Guide for HP-UX System Administrators

Administering a System: Managing Disks and Files

Managing File Systems

Chapter 6 641

disk will be made on the substitute physical volume. This process is

referred to as automatic sparing, or just sparing. This occurs while

the ﬁle system remains available to users. You can then schedule the

replacement of the failed disk at a time of minimal inconvenience to you

and your users. At such time, you would then copy the data from the

spare disk back to the original disk or its replacement and return the

spare disk to its role as a “standby” empty disk.

Follow the steps below to conﬁgure one or more spare physical volumes

into each volume group for which you want protection against disk

failure. These steps must be performed prior to a disk failure actually

occurring.

NOTE MirrorDisk/UX is not available for shared LVM environments within a

high availability cluster. Since MirrorDisk/UX is required for sparing,

you will not be able to conﬁgure sparing using the steps below within

such shared LVM environments. In such cases, it is suggested that you

make use of hardware mirroring through RAID devices. Hardware

mirroring often supports its own form of sparing.

Step 1. Use the pvcreate command to initialize the disk as an LVM disk.

However, do not use the -B option since spare physical volumes cannot

contain boot information.

# pvcreate /dev/rdsk/c1t0d0

Step 2. Make sure the volume group has been activated.

vgchange -a y /dev/vg01

Step 3. Use the vgextend command with -z y to designate one or more physical

volumes as spare physical volumes within the volume group. Alternately,

you can change a physical volume with no extents currently allocated

within it into a spare physical volume using the pvchange command

with the -z y option.

vgextend -z y /dev/vg01 /dev/dsk/c1t0d0

In order for sparing to occur: