Veritas Volume Manager 5.0 Administrator's Guide (September 2006)

425Administering sites and remote mirrors
Although not shown in this figure, DCO log volumes are also mirrored across the sites,
and disk group configuration copies are distributed across the sites.
To enhance read performance, VxVM will service reads from the plexes at the local site
where an application is running if the
siteread read policy is set on a volume. Writes are
written to plexes at all sites.
The site consistency of a volume is ensured by detaching a site when its last complete plex
fails at that site. If a site fails, all its plexes are detached and the site is said to be detached.
Configurations with remote storage only are also supported as illustrated in Figure 14-3.
Figure 14-3 Example of a two-site configuration with remote storage only
Fibre Channel
Hubs/Switches
Site A Site B
Metropolitan
Area Network Link
(such as DWDM)
Cluster or
Standalone
System
Disk
Enclosures
Disk
Enclosures