VERITAS Volume Manager 4.1 Troubleshooting Guide

Recovery from Hardware Failure
Failures on RAID-5 Volumes
Chapter 1 19
- - mydg03 mydg failed was: c1t3d0
- - mydg04 mydg failed was: c1t4d0
2. Once the fault has been corrected, the disks can be reattached by using the following
command to rescan the device list:
# /usr/sbin/vxdctl enable
3. Use the vxreattach command with no options to reattach the disks:
# /etc/vx/bin/vxreattach
After reattachment takes place, recovery may not be necessary unless a disk was faulty and
had to be replaced. Reattachment can fail if the original (or another) cause for the disk failure
still exists.
You can use the command vxreattach-c to check whether reattachment is possible, without
performing the operation. Instead, it displays the disk group and disk media name where the
disk can be reattached.
See the vxreattach(1M) manual page for more information on the vxreattach command.
Failures on RAID-5 Volumes
Failures are seen in two varieties: system failures and disk failures. A system failure means
that the system has abruptly ceased to operate due to an operating system panic or power
failure. Disk failures imply that the data on some number of disks has become unavailable
due to a system failure (such as a head crash, electronics failure on disk, or disk controller
failure).
System Failures
RAID-5 volumes are designed to remain available with a minimum of disk space overhead, if
there are disk failures. However, many forms of RAID-5 can have data loss after a system
failure. Data loss occurs because a system failure causes the data and parity in the RAID-5
volume to become unsynchronized. Loss of synchronization occurs because the status of writes
that were outstanding at the time of the failure cannot be determined.