<?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="concept" /> <meta name="DC.Title" content="Example: Independent disk pools with geographic mirroring" /> <meta name="DC.Relation" scheme="URI" content="rzaigscenarios.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="rzalyexamplegeomirror" /> <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>Example: Independent disk pools with geographic mirroring</title> </head> <body id="rzalyexamplegeomirror"><a name="rzalyexamplegeomirror"><!-- --></a> <!-- Java sync-link --><script language="Javascript" src="../rzahg/synch.js" type="text/javascript"></script> <h1 class="topictitle1">Example: Independent disk pools with geographic mirroring</h1> <div><div class="fignone"><p>The following example shows one way that geographic mirroring can be configured. Node A and Node B are located in New York City. Node C and Node D are located in Boston. All four nodes are configured in the same recovery domain. The production copy can be switched between nodes A and B. The mirror copy can be switched between nodes C and D. Because all of the nodes are in the same recovery domain, the source system in New York can also exchange roles with the target system in Boston, allowing Boston to host the production copy.</p> <img src="rzaly507.gif" alt="Geographic mirroring for an independent disk pool between New York City and Boston" /><div class="p">This company has defined the following roles for the nodes in the recovery domain: <div class="tablenoborder"><table cellpadding="4" cellspacing="0" summary="" frame="border" border="1" rules="all"><thead align="left"><tr><th valign="top" id="d0e25">Node</th> <th valign="top" id="d0e27">Role</th> </tr> </thead> <tbody><tr><td valign="top" headers="d0e25 ">Node A</td> <td valign="top" headers="d0e27 ">Primary</td> </tr> <tr><td valign="top" headers="d0e25 ">Node B</td> <td valign="top" headers="d0e27 ">Backup 1</td> </tr> <tr><td valign="top" headers="d0e25 ">Node C</td> <td valign="top" headers="d0e27 ">Backup 2</td> </tr> <tr><td valign="top" headers="d0e25 ">Node D</td> <td valign="top" headers="d0e27 ">Backup 3</td> </tr> </tbody> </table> </div> In the event of a natural disaster in New York, Node C in Boston becomes the primary node by upgrading its mirror copy to a production copy. Node C becomes the source system for geographic mirroring, although geographic mirroring will be suspended because there is no target node because of the natural disaster in New York. When the New York site recovers, Node A becomes a backup node and its previous production copy becomes the mirror copy.</div> </div> </div> <div> <div class="familylinks"> <div class="parentlink"><strong>Parent topic:</strong> <a href="rzaigscenarios.htm" title="Use these examples of typical cluster implementations to understand when, why, and how using clusters can be beneficial.">Examples: Cluster configurations</a></div> </div> </div> </body> </html>