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

If one node fails, the other nodes can still access the shared disks.
When configured with suitable software, mission-critical applications
can continue running by transferring their execution to a standby
node in the cluster. This ability to provide continuous uninterrupted
service by switching to redundant hardware is commonly termed
failover.
Failover is transparent to users and high-level applications for
database and file-sharing. You must configure cluster management
software, such as Veritas Cluster Server (VCS), to monitor systems
and services, and to restart applications on another node in the event
of either hardware or software failure. VCS also allows you to perform
general administration tasks such as making nodes join or leave a
cluster.
Note that a standby node need not remain idle. It could be used to
serve other applications in parallel.
Availability
Clusters can reduce contention for system resources by performing
activities such as backup, decision support and report generation on
the more lightly loaded nodes of the cluster. This allows businesses
to derive enhanced value from their investment in cluster systems.
Off-host
processing
The cluster functionality of Veritas Volume Manager (CVM) allows up to 32 nodes
in a cluster to simultaneously access and manage a set of disks under VxVM control
(VM disks). The same logical view of disk configuration and any changes to this
is available on all the nodes. When the cluster functionality is enabled, all the
nodes in the cluster can share VxVM objects such as shared disk groups. Private
disk groups are supported in the same way as in a non-clustered environment.
This chapter discusses the cluster functionality that is provided with VxVM.
Note: You need an additional license to use this feature.
Products such as Veritas Storage Foundation Cluster File System (SFCFS), and
Veritas Cluster Server (VCS) are separately licensed, and are not included with
Veritas Volume Manager. See the documentation provided with those products
for more information about them.
For information about administering a cluster that is under the control of HP
Serviceguard, refer to the HP Serviceguard Storage Management Suite
documentation.
The Dynamic Multipathing (DMP) feature of VxVM can be used in a clustered
environment.
See “DMP in a clustered environment” on page 146.
Administering cluster functionality
About the cluster functionality of VxVM
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