76 lines
5.3 KiB
HTML
76 lines
5.3 KiB
HTML
|
<?xml version="1.0" encoding="UTF-8"?>
|
||
|
|
<!DOCTYPE html
|
||
|
|
PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
|
||
|
|
<html lang="en-us" xml:lang="en-us">
|
||
|
|
<head>
|
||
|
|
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
|
||
|
|
<meta name="security" content="public" />
|
||
|
|
<meta name="Robots" content="index,follow" />
|
||
|
|
<meta http-equiv="PICS-Label" content='(PICS-1.1 "http://www.icra.org/ratingsv02.html" l gen true r (cz 1 lz 1 nz 1 oz 1 vz 1) "http://www.rsac.org/ratingsv01.html" l gen true r (n 0 s 0 v 0 l 0) "http://www.classify.org/safesurf/" l gen true r (SS~~000 1))' />
|
||
|
|
<meta name="DC.Type" content="task" />
|
||
|
|
<meta name="DC.Title" content="Writing a highly available cluster application" />
|
||
|
|
<meta name="abstract" content="A highly available application is one that can be resilient to a system outage in a clustered environment." />
|
||
|
|
<meta name="description" content="A highly available application is one that can be resilient to a system outage in a clustered environment." />
|
||
|
|
<meta name="DC.Relation" scheme="URI" content="rzaigapplications.htm" />
|
||
|
|
<meta name="DC.Relation" scheme="URI" content="rzaigapplicationsmakeappsresilient.htm" />
|
||
|
|
<meta name="DC.Relation" scheme="URI" content="rzaigapplicationsrestart.htm" />
|
||
|
|
<meta name="DC.Relation" scheme="URI" content="rzaigapplicationscallcrgexitprogram.htm" />
|
||
|
|
<meta name="copyright" content="(C) Copyright IBM Corporation 1998, 2006" />
|
||
|
|
<meta name="DC.Rights.Owner" content="(C) Copyright IBM Corporation 1998, 2006" />
|
||
|
|
<meta name="DC.Format" content="XHTML" />
|
||
|
|
<meta name="DC.Identifier" content="rzaigapplicationswritehighlyavailable" />
|
||
|
|
<meta name="DC.Language" content="en-us" />
|
||
|
|
<!-- All rights reserved. Licensed Materials Property of IBM -->
|
||
|
|
<!-- US Government Users Restricted Rights -->
|
||
|
|
<!-- Use, duplication or disclosure restricted by -->
|
||
|
|
<!-- GSA ADP Schedule Contract with IBM Corp. -->
|
||
|
|
<link rel="stylesheet" type="text/css" href="./ibmdita.css" />
|
||
|
|
<link rel="stylesheet" type="text/css" href="./ic.css" />
|
||
|
|
<title>Writing a highly available cluster application</title>
|
||
|
|
</head>
|
||
|
|
<body id="rzaigapplicationswritehighlyavailable"><a name="rzaigapplicationswritehighlyavailable"><!-- --></a>
|
||
|
|
<!-- Java sync-link --><script language="Javascript" src="../rzahg/synch.js" type="text/javascript"></script>
|
||
|
|
<h1 class="topictitle1">Writing a highly available cluster application</h1>
|
||
|
|
<div><p>A highly available application is one that can be resilient to
|
||
|
|
a system outage in a clustered environment.</p>
|
||
|
|
<div class="section">Several levels of application availability are possible:</div>
|
||
|
|
<ol><li class="stepexpand"><span>If an application error occurs, the application restarts itself
|
||
|
|
on the same node and corrects any potential cause for error (such as corrupt
|
||
|
|
control data). You can view the application as though it had started for
|
||
|
|
the first time.</span></li>
|
||
|
|
<li class="stepexpand"><span>The application performs some amount of checkpoint-restart processing.
|
||
|
|
You can view the application as if it were close to the point of failure.</span></li>
|
||
|
|
<li class="stepexpand"><span>If a system outage occurs, the application is restarted on a backup
|
||
|
|
server. You can view the application as though it had started for the first
|
||
|
|
time.</span></li>
|
||
|
|
<li class="stepexpand"><span>If a system outage occurs, the application is restarted on a backup
|
||
|
|
server and performs some amount of checkpoint-restart processing across the
|
||
|
|
servers. You can view the application as if it were close to the point of
|
||
|
|
failure.</span></li>
|
||
|
|
<li class="stepexpand"><span>If a system outage occurs, a coordinated failover of both the application
|
||
|
|
and its associated data to another node or nodes in the cluster occurs. You can view the application as though it had started for the first
|
||
|
|
time.</span></li>
|
||
|
|
<li class="stepexpand"><span>If a system outage occurs, a coordinated failover of both the application
|
||
|
|
and its associated data to another node or nodes in the cluster occurs. The application performs some amount of checkpoint-restart processing
|
||
|
|
across the servers. You can view the application as if it were close to
|
||
|
|
the point of failure.</span> <div class="note"><span class="notetitle">Note:</span> In cases 1 through 4 above, you are
|
||
|
|
responsible for recovering the data.</div>
|
||
|
|
</li>
|
||
|
|
</ol>
|
||
|
|
</div>
|
||
|
|
<div>
|
||
|
|
<ul class="ullinks">
|
||
|
|
<li class="ulchildlink"><strong><a href="rzaigapplicationsmakeappsresilient.htm">Make application programs resilient</a></strong><br />
|
||
|
|
Learn how to make application programs resilient.</li>
|
||
|
|
<li class="ulchildlink"><strong><a href="rzaigapplicationsrestart.htm">Restart highly available cluster applications</a></strong><br />
|
||
|
|
To restart an application, the application needs to know its state at the time of the failover or switchover.</li>
|
||
|
|
<li class="ulchildlink"><strong><a href="rzaigapplicationscallcrgexitprogram.htm">Calling a cluster resource group exit program</a></strong><br />
|
||
|
|
The cluster resource group exit program is called during different phases of a cluster environment.</li>
|
||
|
|
</ul>
|
||
|
|
|
||
|
|
<div class="familylinks">
|
||
|
|
<div class="parentlink"><strong>Parent topic:</strong> <a href="rzaigapplications.htm" title="Application resilience is one of the key elements in a clustered environment. If you are planning to write and use highly available applications in your cluster you should be aware that these applications have specific availability specifications.">Cluster applications</a></div>
|
||
|
|
</div>
|
||
|
|
</div>
|
||
|
|
</body>
|
||
|
|
</html>
|