< Previous  | TOC | Index | Next  >

Supported volume logs and maps

Veritas Volume Manager supports the use of the following types of logs and maps with volumes:

• FastResync Maps are used to perform quick and efficient resynchronization of mirrors.

  See "FastResync" on page 68.

  These maps are supported either in memory (Non-Persistent FastResync), or on disk as part of a DCO volume (Persistent FastResync). Two types of DCO volume are supported:

  • Version 0 DCO volumes only support Persistent FastResync for the traditional third-mirror break-off type of volume snapshot.

    See "Version 0 DCO volume layout" on page 71.

    See "Creating a volume with a version 0 DCO volume" on page 260.

  • Version 20 DCO volumes, introduced in VxVM 4.0, support DRL logging (see below) and Persistent FastResync for full-sized and space-optimized instant volume snapshots.

    See "Version 20 DCO volume layout" on page 71.

    See "Creating a volume with a version 20 DCO volume" on page 261.

    See "Enabling FastResync on a volume" on page 302.

• Dirty region logs allow the fast recovery of mirrored volumes after a system crash.

  See "Dirty region logging" on page 61.

  These logs are supported either as DRL log plexes, or as part of a version 20 DCO volume. Refer to the following sections for information on creating a volume on which DRL is enabled:

  See "Creating a volume with dirty region logging enabled" on page 262.

  See "Creating a volume with a version 20 DCO volume" on page 261.

• RAID-5 logs are used to prevent corruption of data during recovery of RAID-5 volumes.

  See "RAID-5 logging" on page 52.

  These logs are configured as plexes on disks other than those that are used for the columns of the RAID-5 volume.

  See "Creating a RAID-5 volume" on page 266.