ibm-information-center/dist/eclipse/plugins/i5OS.ic.rzaig_5.4.0.1/rzaigconceptsswitchover.htm

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<h1 class="topictitle1">Switchover</h1>
<div><p><dfn class="term">Switchover</dfn> happens when you manually
switch access to a resource from one server to another.</p>
<div class="section"><p>You usually initiate a manual switchover if you wanted to perform
system maintenance, such as applying program temporary fixes (PTFs), installing
a new release, or upgrading your system. Contrast this with a failover, which
happens automatically when a outage occurs on the primary node.</p>
<p>When
a switchover occurs, access is switched from the cluster node currently acting
as the primary node in the recovery domain of the cluster resource group to
the cluster node designated as the first backup. See recovery domain for information
on how the switchover order is determined.</p>
<p>If you are doing an administrative
switchover of multiple CRGs, the order you specify should consider the relationships
between the CRGs. For example, if you have an application CRG that depends
on data associated with a device CRG, the steps to an ordered switchover are:</p>
</div>
<ol><li><span>Stop the application on the old primary node (to quiesce changes
to the data).</span></li>
<li><span>Switch the device CRG to the new primary node.</span></li>
<li><span>Switch the application CRG to the new primary node.</span></li>
<li><span>Restart the application on the new primary node.</span></li>
</ol>
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<div class="familylinks">
<div class="parentlink"><strong>Parent topic:</strong> <img src="./delta.gif" alt="Start of change" /><a href="rzaigconceptsevents.htm" title="Within a cluster several types events, actions, and services can occur.">Cluster events</a><img src="./deltaend.gif" alt="End of change" /></div>
</div>
<div class="relconcepts"><strong>Related concepts</strong><br />
<div><a href="rzaigconceptsfailover.htm" title="Failover occurs when a server in a cluster automatically switches over to one or more backup servers in the event of a system failure.">Failover</a></div>
<div><a href="rzaigconceptsrecoverydomain.htm" title="A recovery domain is a subset of cluster nodes that are grouped together in a cluster resource group (CRG) for a common purpose such as performing a recovery action or synchronizing events.">Recovery domain</a></div>
</div>
<div class="reltasks"><strong>Related tasks</strong><br />
<div><a href="rzaigmanageperformswitchover.htm" title="Performing a manual switchover causes the current primary node to switch over to the backup node, as defined in the cluster resource group's recovery domain.">Perform a switchover</a></div>
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