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
Planning your backup strategy80
