VERITAS Volume Manager 3.2 for HP-UX Release Notes

VxVM and Multi-Host Failover Configurations

Chapter 1 29

VxVM can support failover, but it relies on the administrator or on an external high

availability monitor to ensure that the first system is really shut down or unavailable before

the disk group is imported to another system. For details on how to clear locks and force an

import, refer to the vxdg (1M)manual page and the section on moving disk groups between

systems in Chapter 2 of the VERITAS Volume Manager (VxVM) Command Line Interface

Guide.

CAUTION If vxdg import is used with -C (clears locks) and/or -f (forces import) to

import a disk group that is still in use from another host, disk group

configuration corruption is very likely to occur. Volume content corruption is

also likely if a file system or database is started on the imported volumes before

the other host crashes or shuts down.

If this kind of corruption occurs, it is likely that you have to rebuild your

configuration from scratch and reload all volumes in the disk group from a

backup. There are typically a large number of configuration copies for each disk

group, but corruption nearly always affects all configuration copies, so

redundancy does not help in this case.

To facilitate reconstruction of a corrupted disk group, it is highly recommended

that the output of “vxprint-mspvd” be saved on a regular basis. This output

should be saved onto a different disk group. When needed, “vxmake...” uses

this output directly to recreate the disk group configuration. When the disk

group is reconfigured, data from backup media can be restored.

Disk group configuration corruption usually shows up as missing or duplicate

records in the configuration databases. This can result in a wide variety of

vxconfigd error messages, including errors such as:

Association not resolved

Association count is incorrect

Duplicate record in configuration

Configuration records are inconsistent

These errors are typically reported in association with specific disk group

configuration copies, but usually apply to all copies. The following is usually

displayed along with the error:

Disk group has no valid configuration copies

See Appendix A of the VERITAS Volume Manager (VxVM) System

Administrator’s Guide for more information on VxVM error messages.

If you use the VERITAS Cluster Server product, all disk group failover issues can be managed

correctly. Cluster Server includes a high availability monitor and failover scripts for VxVM,