Veritas Volume Manager 4.1 Administrator's Guide (HP-UX 11i v3, February 2007)

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Administering Cluster Functionality

Note The cluster functionality feature is not supported by VxVM 4.1 on the HP-UX 11i v3

platform.

A cluster consists of a number of hosts or nodes that share a set of disks. The main benefits

of cluster configurations are:

◆ Availability—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.

◆ Off-host processing—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.

The cluster functionality of VERITAS Volume Manager (CVM) allows up to 16 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. This chapter discusses the cluster functionality that is provided with

VxVM.

Note You need an additional license to use this feature.

This chapter does not discuss VERITAS Cluster File System (CFS) nor cluster management

software such as VERITAS Cluster Server (VCS). Such products are separately licensed,

and are not included with VERITAS Volume Manager. See the documentation provided

with those products for more information about them.