About the cluster functionality of VxVM

A cluster consists of a number of hosts or nodes that share a set of disks. The following are the main benefits of cluster configurations:

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.

Note that a standby node need not remain idle. It could be used to serve other applications in parallel.

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 nodes can simultaneously access and manage a set of disks or LUNs under Veritas Volume Manager (VxVM) control. The same logical view of disk configuration and any changes to this view are available on all the nodes. When the CVM functionality is enabled, all cluster nodes can share VxVM objects such as shared disk groups. Private disk groups are supported in the same way as in a non-clustered environment.

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.

Veritas Dynamic Multi-Pathing (DMP) can be used in a clustered environment.

Campus cluster configurations (also known as stretch cluster or remote mirror configurations) can also be configured and administered.

More Information

DMP in a clustered environment

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