54 lines
2.9 KiB
HTML
54 lines
2.9 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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<head>
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<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
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<meta name="security" content="public" />
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<meta name="Robots" content="index,follow" />
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<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))' />
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<meta name="DC.Type" content="topic" />
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<meta name="DC.Title" content="Costs and limitations of device parity protection" />
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<meta name="DC.Relation" scheme="URI" content="rzalydpp.htm" />
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<meta name="copyright" content="(C) Copyright IBM Corporation 2002, 2006" />
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<meta name="DC.Rights.Owner" content="(C) Copyright IBM Corporation 2002, 2006" />
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<meta name="DC.Format" content="XHTML" />
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<meta name="DC.Identifier" content="hdrdeviceparitycost" />
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<meta name="DC.Language" content="en-us" />
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<!-- All rights reserved. Licensed Materials Property of IBM -->
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<!-- US Government Users Restricted Rights -->
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<!-- Use, duplication or disclosure restricted by -->
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<!-- GSA ADP Schedule Contract with IBM Corp. -->
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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>Costs and limitations of device parity protection</title>
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</head>
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<body id="hdrdeviceparitycost"><a name="hdrdeviceparitycost"><!-- --></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 device parity protection</h1>
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<div><p>Here are the costs and limitations of device parity protection:</p>
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<ul><li>Device parity protection can require additional disk units to prevent
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slower performance.</li>
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<li>Restore operations can take longer when you use device parity protection.</li>
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</ul>
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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="rzalydpp.htm">Device parity protection</a></div>
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</div>
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</div><div class="nested1" xml:lang="en-us" id="raid-5"><a name="raid-5"><!-- --></a><h2 class="topictitle2">RAID 5</h2>
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<div><p>The system is only capable of handling one disk-unit failure.
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If more than one disk unit fails, the system may also fail depending on the
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ASP configuration.</p>
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</div>
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</div>
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<div class="nested1" xml:lang="en-us" id="raid-6"><a name="raid-6"><!-- --></a><h2 class="topictitle2">RAID 6</h2>
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<div><p>The system is capable of handling up to two disk-unit failures.
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However, because the amount of parity data is twice as much as parity data
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in RAID 5, the available storage for user data is reduced. If more than two
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disk units fail, the system may also fail depending on the ASP configuration.</p>
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</div>
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</div>
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</body>
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</html>
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