67 lines
3.7 KiB
HTML
67 lines
3.7 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.Title" content="Costs and limitations of geographic mirroring" />
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<meta name="copyright" content="(C) Copyright IBM Corporation 2002, 2006" />
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<link rel="stylesheet" type="text/css" href="./ic.css" />
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<title>Costs and limitations of geographic mirroring</title>
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</head>
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<body id="rzalygeocosts"><a name="rzalygeocosts"><!-- --></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">Costs and limitations of geographic mirroring</h1>
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<div><div class="section"><h4 class="sectiontitle">Costs</h4><p>To configure geographic mirroring between
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two sites, the following items are required:</p>
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<div class="p"><ul><li>At least one iSeries™ server
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at each site. </li>
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<li>Sufficient CPU support for the additional CPU capacity required
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for geographic mirroring. A fraction of a processor for a partition supporting
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geographic mirroring is not adequate.</li>
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<li>Sufficient disk units at each site for the production and
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the mirror copy of the geographically mirrored independent disk pools. To
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avoid disk unit contention, use separate input/output adapters for the production
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copy on its node and for the mirror copy on its node.</li>
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<li>One TCP/IP connection from each node should
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connect the two sites. A second TCP/IP connection is strongly recommended
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to provide redundancy and better performance. You may configure up to four
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TCP/IP connections. See <a href="rzalycommunications.htm">Communications requirements</a> for
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more information.</li>
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</ul>
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</div>
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</div>
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<div class="section"><h4 class="sectiontitle">Limitations</h4><div class="p">Limitations
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of geographic mirroring include these constraints:<ul><li>When geographic mirroring is being performed, you cannot access the mirror
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copy; this ensures that the data integrity of the mirror copy is maintained.</li>
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<li>If you detach the mirror copy to perform a save operation, to perform
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data mining, or to create reports, you must reattach the mirror copy to resume
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geographic mirroring. The mirror copy must be synchronized with the production
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copy after it is reattached. Synchronization can be a lengthy process.</li>
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<li>Synchronization can be a lengthy process, especially if geographic mirroring
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was suspended without tracking.</li>
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</ul>
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</div>
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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> <a href="rzalygeographicmirror.htm">Geographic mirroring</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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