Cluster Administration; Cluster Overview - HP ML110 - ProLiant G5 2TB Storage Server NAS User Manual

9 Cluster administration

NOTE:
Not all HP ProLiant Storage Servers can be clustered. See the HP ProLiant Storage Server QuickSpecs to
determine if your storage server can be clustered. Windows Storage Server 2003 Release 2 clusters can
include up to eight nodes.
One important feature of the HP ProLiant Storage Server clusterable models is that they can operate
as a single node or as a cluster. This chapter discusses cluster installation and cluster management
issues.

Cluster overview

Up to eight server nodes can be connected to each other and deployed as a no single point of failure
(NSPOF) cluster. Utilizing a private network allows communication amongst themselves in order to
track the state of each cluster node. Each node sends out periodic messages to the other nodes; these
messages are called heartbeats. If a node stops sending heartbeats, the cluster service fails over any
resources that the node owns to another node. For example, if the node that owns the Quorum disk
is shut down for any reason, its heartbeat stops. The other nodes detect the lack of the heartbeat and
another node takes over ownership of the Quorum disk and the cluster.
Clustering servers greatly enhances the availability of file serving by enabling file shares to fail over
to additional storage servers if problems arise. Clients see only a brief interruption of service as the
file share resource transitions from one server node to the other.
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