Figure 19 Typical cluster

Components:

•Cluster nodes (two or more)

•Local disks

•Shared disks (shared between nodes)

Cluster nodes

Cluster nodes are computers that compose a cluster. They are physically connected to one or more shared disks.

Shared disks

The shared disks volumes (MSCS, Novell NetWare Cluster Services) or shared volume groups (MC/SG, Veritas Cluster) contain mission-critical application data as well as specific cluster data needed to run the cluster. In MSCS clusters, a shared disk is exclusively active on only one cluster node at a time.

Cluster network

A cluster network is a private network that connects all cluster nodes. It transfers the internal cluster data called heartbeat of the cluster. The heartbeat is a data packet with a time stamp that is distributed among all cluster nodes. Each cluster node compares this packet and determines the cluster node that is still operational so that

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Planning your backup strategy