Veritas Volume Manager 5.0 Troubleshooting Guide, HP-UX 11i v3, First Edition, May 2008

20 Recovery from hardware failure

Failures on RAID-5 volumes

configuration database. The -o checkpt=size option controls how often the

checkpoint is saved. If the option is not specified, the default checkpoint size is

used.

Because saving the checkpoint offset requires a transaction, making the

checkpoint size too small can extend the time required to regenerate parity.

After a system reboot, a RAID-5 volume that has a checkpoint offset smaller

than the volume length starts a parity resynchronization at the checkpoint

offset.

Log plex recovery

RAID-5 log plexes can become detached due to disk failures. These RAID-5 logs

can be reattached by using the att keyword for the

vxplex command. To

reattach the failed RAID-5 log plex, use the following command:

# vxplex -g mydg att r5vol r5vol-l1

Stale subdisk recovery

Stale subdisk recovery is usually done at volume start time. However, the

process doing the recovery can crash, or the volume may be started with an

option such as

-o delayrecover that prevents subdisk recovery. In addition, the

disk on which the subdisk resides can be replaced without recovery operations

being performed. In such cases, you can perform subdisk recovery using the

vxvol recover command. For example, to recover the stale subdisk in the RAID-

5 volume shown in the figure “Invalid RAID-5 volume” on page 22, use the

following command:

# vxvol -g mydg recover r5vol disk05-00

A RAID-5 volume that has multiple stale subdisks can be recovered in one

operation. To recover multiple stale subdisks, use the

vxvol recover command

on the volume, as follows:

# vxvol -g mydg recover r5vol

Recovery after moving RAID-5 subdisks

When RAID-5 subdisks are moved and replaced, the new subdisks are marked as

STALE in anticipation of recovery. If the volume is active, the

vxsd command

may be used to recover the volume. If the volume is not active, it is recovered

when it is next started. The RAID-5 volume is degraded for the duration of the

recovery operation.