Veritas Volume Manager 5.0.1 Administrator's Guide, HP-UX 11i v3, First Edition, November 2009

place, are instead divided between two or more sites. These sites are typically
connected via a redundant high-capacity network that provides access to storage
and private link communication between the cluster nodes.
Figure 14-1 shows a typical two-site remote mirror configuration.
Figure 14-1
Example of a two-site remote mirror configuration
Cluster
nodes
Fibre Channel
hub or switch
Fibre Channel
hub or switch
Disk enclosures Disk enclosures
Site A
Private network
Site B
Metropolitan or
wide area
network link
(Fibre Channel
or DWDM)
Cluster
nodes
If a disk group is configured across the storage at the sites, and inter-site
communication is disrupted, there is a possibility of a serial split brain condition
arising if each site continues to update the local disk group configuration copies.
See “Handling conflicting configuration copies” on page 221.
VxVM provides mechanisms for dealing with the serial split brain condition,
monitoring the health of a remote mirror, and testing the robustness of the cluster
against various types of failure (also known as fire drill).
For applications and services to function correctly at a site when other sites have
become inaccessible, at least one complete plex of each volume must be configured
at each site (site-based allocation), and the consistency of the data in the plexes
at each site must be ensured (site consistency).
Administering sites and remote mirrors
About sites and remote mirrors
488