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. By tagging hosts with site information, VxVM identifies which hosts belong to which site. Reads initiated by a host from one site are then satisfied by disks which are tagged with the same site. Tagging hosts and disks with correct site information gives you maximum read performance when siteread read policy is used.

If a license enabling the Site Awareness feature 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 the siteread policy is not set, use the following command to set the read policy to 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.