78 lines
5.7 KiB
HTML
78 lines
5.7 KiB
HTML
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<?xml version="1.0" encoding="UTF-8"?>
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<!DOCTYPE html
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PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
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<html lang="en-us" xml:lang="en-us">
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<meta name="DC.Type" content="concept" />
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<meta name="DC.Title" content="Heartbeat monitoring" />
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<meta name="abstract" content="Heartbeat monitoring is a cluster resource services function that ensures that each node is active by sending a signal from every node in the cluster to every other node in the cluster to convey that they are still active." />
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<meta name="description" content="Heartbeat monitoring is a cluster resource services function that ensures that each node is active by sending a signal from every node in the cluster to every other node in the cluster to convey that they are still active." />
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<meta name="DC.Relation" scheme="URI" content="rzaigconceptsevents.htm" />
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<meta name="DC.Relation" scheme="URI" content="rzaigmanage.htm" />
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<meta name="DC.Relation" scheme="URI" content="rzaigmanagemonitor.htm" />
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<meta name="DC.Relation" scheme="URI" content="rzaigmanageclusterperformance.htm" />
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<meta name="copyright" content="(C) Copyright IBM Corporation 1998, 2006" />
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<link rel="stylesheet" type="text/css" href="./ibmdita.css" />
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<link rel="stylesheet" type="text/css" href="./ic.css" />
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<title>Heartbeat monitoring</title>
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</head>
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<body id="rzaigconceptsheartbeatmonitor"><a name="rzaigconceptsheartbeatmonitor"><!-- --></a>
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<!-- Java sync-link --><script language="Javascript" src="../rzahg/synch.js" type="text/javascript"></script>
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<h1 class="topictitle1">Heartbeat monitoring</h1>
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<div><p><dfn class="term">Heartbeat monitoring</dfn> is a cluster resource services
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function that ensures that each node is active by sending a signal from every
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node in the cluster to every other node in the cluster to convey that they
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are still active.</p>
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<p><img src="./delta.gif" alt="Start of change" />When the heartbeat for a node fails, cluster resource services
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takes the appropriate action.<img src="./deltaend.gif" alt="End of change" /></p>
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<p>Consider the following examples to understand how heartbeat monitoring
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works:</p>
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<div class="section"><h4 class="sectiontitle">Example 1</h4><br /><img src="rv4c102.gif" alt="Heartbeat monitor example." /><br /><p>With the default (or normal) settings, a heartbeat
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message is sent every 3 seconds from every node in the cluster to its upstream
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neighbor. For example, if you configure Node A, Node B, and Node C on Network
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1, Node A sends a message to Node B, Node B sends a message to Node C, and
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Node C sends a message to Node A. Node A expects an acknowledgment to the
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heartbeat from Node B as well as an incoming heartbeat from the downstream
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Node C. In effect, the heartbeating ring goes both ways. If Node A did not
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receive a heartbeat from Node C, Node A and Node B continues to send a heartbeat
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every 3 seconds. If Node C missed four consecutive heartbeats, a heartbeat
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failure is signaled.</p>
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</div>
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<div class="section"><h4 class="sectiontitle">Example 2</h4><img src="rv4c101.gif" alt="Heartbeat monitor with routers example." /><p>Let's add another network to this example to
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show how routers and relay nodes are used. You configure Node D, Node E, and
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Node F on Network 2. Network 2 is connected to Network 1 using a router. A
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router can be another iSeries™ server or a router box that directs communications
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to another router somewhere else. Every local network is assigned a relay
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node. This relay node is assigned to the node that has the lowest node ID
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in the network. Node A is assigned as the relay node on Network 1, and Node
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D is assigned as the relay node on Network 2. A logical network containing
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Node A and Node D is then created. By using routers and relay nodes, the nodes
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on these two networks can monitor each other and signal any node failures.</p>
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</div>
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</div>
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<div>
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<div class="familylinks">
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<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>
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</div>
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<div class="relconcepts"><strong>Related concepts</strong><br />
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<div><a href="rzaigmanage.htm" title="This topic contains information that covers some of the tasks that involve managing your clusters.">Manage clusters</a></div>
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<div><a href="rzaigmanageclusterperformance.htm" title="When changes are made to a cluster, the overhead necessary to manage the cluster can be affected.">Cluster performance</a></div>
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</div>
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<div class="reltasks"><strong>Related tasks</strong><br />
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<div><a href="rzaigmanagemonitor.htm" title="Taking appropriate actions when necessary, the cluster resource services performs basic monitoring of a cluster and its components using the reliable message function and heartbeat monitoring.">Monitor cluster status</a></div>
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</div>
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</div>
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</body>
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</html>
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