HP Veritas Volume Manager 5.0 -UX 11i v3 manual Adding logs and maps to volumes

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Administering volumes

Adding logs and maps to volumes

This command removes the mirror vol01-02and all associated subdisks. This is equivalent to entering the following separate commands:

#vxplex -g mydg dis vol01-02

#vxedit -g mydg -r rm vol01-02

Adding logs and maps to volumes

In Veritas Volume Manager, several types of volume logs and maps are supported:

■FastResync Maps are used to perform quick and efficient resynchronization of mirrors (see “FastResync” on page 66 for details). These maps are supported either in memory (Non-PersistentFastResync), or on disk as part of a DCO volume (Persistent FastResync). Two types of DCO volumes are supported:

■Version 0 DCO volumes only support Persistent FastResync for the traditional third-mirrorbreak-off type of volume snapshot. See “Version 0 DCO volume layout” on page 69, and “Adding a version 0 DCO and DCO volume” on page 356 for more information.

■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 69, and “Preparing a volume for DRL and instant snapshots” on page 275 for more information.

See “Enabling FastResync on a volume” on page 292 for information on how to enable Persistent or Non-Persistent FastResync on a volume.

■Dirty Region Logs allow the fast recovery of mirrored volumes after a system crash (see “Dirty region logging” on page 60 for details). 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 enabling DRL on a volume:

■“Adding traditional DRL logging to a mirrored volume” on page 281 describes how to add DRL log plexes to a volume.

■“Preparing a volume for DRL and instant snapshots” on page 275 describes how to configure DRL for a volume using a version 20 DCO volume.

■RAID-5 logs are used to prevent corruption of data during recovery of RAID- 5 volumes (see “RAID-5 logging” on page 50 for details). These logs are configured as plexes on disks other than those that are used for the columns of the RAID-5 volume.

See “Adding a RAID-5 log” on page 283 for information on adding RAID-5 logs to a RAID-5 volume.