About the cluster functionality of VxVM


About the cluster functionality of VxVM
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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 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.

Storage Foundation Cluster File System High Availability (SFCFSHA) includes the Cluster Volume Manager (CVM) as a component. CVM expands the functionality of Veritas Volume Manager (VxVM) to add support for a clustered environment. CVM enables the cluster nodes to simultaneously access and manage a set of disks or LUNs under 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.