Protecting Your System

Use mirroring to protect data. By mirroring your data, you prevent data loss from a disk failure. To preserve data, create and use mirrored volumes that have at least two data plexes. The plexes must be on different disks. If a disk failure causes a plex to fail, the data in the mirrored volume still exists on the other disk.

If you use the vxassist mirror command to create mirrors, it locates the mirrors so the loss of one disk does not result in a loss of data. By default, the vxassist command does not create mirrored volumes; edit the file /etc/default/vxassist to set the default layout to mirrored. For information on the vxassist defaults file, see “vxassist Command”.

Leave the Volume Manager hot-relocation feature enabled to automatically detect failures, notify you of the nature of the failures, attempt to relocate any affected subdisks that are redundant, and initiate recovery procedures. Provide at least one hot-relocation spare disk per disk group so sufficient space is available for relocation in the event of a failure.

For mirrored volumes, take advantage of the Dirty Region Logging feature to speed up recovery of your mirrored volumes after a system crash. Make sure that each mirrored volume has at least one log subdisk. (Note that the usr volume cannot have Dirty Region Logging turned on.)

For RAID-5 volumes, take advantage of logging to prevent corruption of recovery data. Make sure that each RAID-5 volume has at least one log plex.

Perform regular backups to protect your data. Backups are necessary if all copies of a volume are lost or corrupted in some way. For example, a power surge could damage several (or all) disks on your system. Also, typing a command in error can remove critical files or damage a file system directly.