Administrator's Guide

The physical process of restarting one of the nodes of a cluster is the same as restarting a storage
system in single node environment. However, additional caution is needed.
Restarting a cluster node causes all cluster resources served by that node to fail over to the other
nodes in the cluster based on the failover policy in place. Until the failover process completes, any
currently executing read and write operations will fail. Other node(s) in the cluster will be placed
under a heavier load by the extra work until the restarted node comes up and the resources are
moved back.
Shutting down one cluster node
CAUTION: Shutting down a cluster node must be done only after confirming that the other node(s)
in the cluster are functioning normally. Adequate warning should be given to users connected to
resources of the node being shutdown.
Shutting down a cluster node causes all cluster resources served by that node to fail over to the
other node(s). This causes any currently executing client read and write operations to fail until the
cluster failover process completes. The other node(s) are placed under a heavier load by the extra
work until the second node is powered up and rejoins the cluster.
Powering down the cluster
The power down process for the storage system cluster is similar to the process for a single node,
but with the cluster, extra care must be taken with the storage subsystem and the sequence of the
shutdown.
The power down process is divided into two main steps:
1. Shutting down the cluster nodes
2. Removing power from the cluster nodes
The sequence of these steps is critical. The devices must be shut down before the storage subsystem.
Improperly shutting down the nodes and the storage subsystem causes corruption and loss of data.
CAUTION: Before powering down the cluster nodes, follow the proper shutdown procedure as
previously illustrated. See “Shutting down one cluster node” (page 72). Only one cluster node
should be shut down at a time.
Powering up the cluster
The power up process for the storage system cluster is more complex than it is for a single node
because extra care must be taken with the storage subsystem.
The sequence of the power up steps is critical. Improper power up procedures can cause corruption
and loss of data.
CAUTION: Do not power up the cluster nodes without first powering up the storage subsystem,
and verifying it is operating normally.
Nodes should be powered up separately allowing one node to form the cluster prior to powering
up the additional node(s). To power up the cluster nodes:
1. After the storage subsystem is confirmed to be operating normally, power up a single node.
Wait for the node to come completely up before powering up the subsequent node(s).
If more than one node is powered up at the same time, the first node that completes the
sequence gains ownership of the cluster quorum and controls the cluster database. Designate
a particular node as the usual cluster quorum owner by always powering up that node first
and letting it completely restart before powering up additional cluster node(s).
2. Power up the additional cluster node(s). Each node should be allowed to start fully, prior to
starting a subsequent node.
72 Cluster administration