Configuring Veritas Volume Manager 513

Guidelines for configuring storage

groups. Storage pools are only required if you intend using the ISP feature of VxVM.

Guidelines for configuring storage

A disk failure can cause loss of data on the failed disk and loss of access to your system. Loss of access is due to the failure of a key disk used for system operations. Veritas Volume Manager can protect your system from these problems.

To maintain system availability, data important to running and booting your system must be mirrored. The data must be preserved so it can be used in case of failure.

The following are suggestions for protecting your system and data:

■Perform regular backups to protect your data. Backups are necessary if all copies of a volume are lost or corrupted. Power surges can damage several (or all) disks on your system. Also, typing a command in error can remove critical files or damage a file system directly. Performing regular backups ensures that lost or corrupted data is available to be retrieved.

■Place the disk containing the root file system (the root or boot disk) under Veritas Volume Manager control. Mirror the root disk so that an alternate root disk exists for booting purposes. By mirroring disks critical to booting, you ensure that no single disk failure leaves your system unbootable and unusable. For more information, see “Rootability” on page 102.

■Use mirroring to protect data against loss from a disk failure. See “Mirroring guidelines” on page 514 for details.

■Use the DRL feature to speed up recovery of mirrored volumes after a system crash. See “Dirty region logging guidelines” on page 515 for details.

■Use striping to improve the I/O performance of volumes. See “Striping guidelines” on page 515 for details.

■Make sure enough disks are available for a combined striped and mirrored configuration. At least two disks are required for the striped plex, and one or more additional disks are needed for the mirror.

■When combining striping and mirroring, never place subdisks from one plex on the same physical disk as subdisks from the other plex.

■Use logging to prevent corruption of recovery data in RAID-5 volumes. Make sure that each RAID-5 volume has at least one log plex. See “RAID-5 guidelines” on page 516 for details.