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

428 Administering sites and remote mirrors
Setting the siteread policy on a volume
Note: The siteconsistent and allsites attributes must be set to off for RAID-5
volumes in a site-consistent disk group.
Setting the siteread policy on a volume
If the Site Awareness license is installed on all the hosts in the Remote Mirror
configuration, the disk group is configured for site consistency with several sites enabled,
and the
allsites=on attribute is specified for a volume, the default read policy is
siteread.
If required, you can use the following command to set the
siteread policy on a volume:
# vxvol [-g diskgroup] rdpol siteread volume
This command has no effect if a site name has not been set for the host.
See “Changing the read policy for mirrored volumes” on page 281.
Site-based allocation of storage to volumes
The vxassist command can be used to create volumes only from storage that exists at a
specified site, as shown in this example:
# vxassist -g diskgroup make volume size site:site1 \
[allsites={on|off}] [siteconsistent={on|off}]
The storage class site is used in similar way to other storage classes with the vxassist
command, such as
enclr, ctlr and disk.
See “Mirroring across targets, controllers or enclosures” on page 247.
Note: If the Site Awareness license is installed on all the hosts in the Remote Mirror
configuration, and site consistency is enabled on a volume, the
vxassist command
attempts to allocate storage across the sites that are registered to a disk group. If not
enough storage is available at all sites, the command fails unless you also specify the
allsites=off attribute.
By default, the
allsites attribute is set to on for volume in a site-consistent disk group.
The
allsites and siteconsistent attributes must be set to off for RAID-5 volumes
in a site-consistent disk group.
In a similar way to mirroring across controllers, you can also ensure that plexes are created
at all sites that are registered for a disk group:
# vxassist -g diskgroup make volume size mirror=site
The allsites and siteconsistent attributes can be combined to create a
non-site-consistent mirrored volume with plexes only at some of the sites: