90 lines
5.6 KiB
HTML
90 lines
5.6 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="Manage performance in optical media libraries" />
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<meta name="abstract" content="This topic describes performance considerations for users of optical media libraries." />
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<meta name="description" content="This topic describes performance considerations for users of optical media libraries." />
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<meta name="DC.Relation" scheme="URI" content="rzam4perfoptmedlib.htm" />
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<title>Manage performance in optical media libraries</title>
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</head>
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<body id="rzam4mgeperfoptmedlib"><a name="rzam4mgeperfoptmedlib"><!-- --></a>
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<img src="./delta.gif" alt="Start of change" /><!-- Java sync-link --><script language="Javascript" src="../rzahg/synch.js" type="text/javascript"></script>
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<h1 class="topictitle1">Manage performance in optical media libraries</h1>
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<div><p>This topic describes performance considerations for users of optical
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media libraries.</p>
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<p>Several factors can affect the optical performance of both LAN-attached
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and directly-attached optical media libraries. This topic explains
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how these factors can influence optical performance. </p>
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<div class="section"><h4 class="sectiontitle">Volume mounting and dismounting</h4><p>Volume mounting
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and dismounting are important factors that affect optical performance. It
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takes approximately 8 to 15 seconds to remove a volume, store it in a slot,
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retrieve a new volume, and mount it. If you can minimize the number of volume
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mounts and dismounts that your application requires, optical performance will
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improve.</p>
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</div>
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<div class="section"><h4 class="sectiontitle">Drive contention</h4><p>Performance can be severely affected
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by drive contention. The following conditions increase drive contention and
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should be avoided:</p>
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<ul><li>Only one drive is available for use by applications libraries.</li>
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<li>Many optical processes are running that attempt to use different optical
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volumes at the same time.</li>
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</ul>
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</div>
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<div class="section"><h4 class="sectiontitle">Number of directories and files</h4><p>Performance can
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be affected by having too few directories with too many files. Directories
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group related information to provide a means of quicker access. Typically,
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you get better performance from more directories with fewer files. Although
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there is no enforced limit on how many files there can be in a directory,
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you probably should not have more than 6000 for performance reasons.</p>
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</div>
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<div class="section"><h4 class="sectiontitle">File size</h4><p>The size of a file has a direct effect
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on the amount of time it takes to read, write, or copy the file. In general,
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the larger the file, the longer the operation can be expected to take.</p>
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</div>
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<div class="section"><h4 class="sectiontitle">Add optical cartridge performance</h4><p> Specifying *NO
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for the Rebuild Directory Index can improve the performance of <span class="cmdname">Add
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Optical Cartridge (ADDOPTCTG)</span> by deferring the build of the optical
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directory index until a later time. </p>
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</div>
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</div>
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<div>
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<ul class="ullinks">
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<li class="ulchildlink"><strong><a href="rzam4perfoptmedlib.htm">Performance considerations for directly-attached optical media libraries</a></strong><br />
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This topic discusses performance considerations that are specific to directly-attached optical libraries.</li>
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</ul>
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<div class="familylinks">
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<div class="parentlink"><strong>Parent topic:</strong> <a href="rzam4optical.htm" title="This topic provides an overview and reference guide for IBM optical support on the iSeries server with the i5/OS operating system.">Optical storage</a></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="../rzau8/considerations.htm">Volume, directory, and file considerations</a></div>
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<div><a href="../rzau8/bufferio.htm">Expanding buffer I/O through HFS</a></div>
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</div>
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<div class="relinfo"><strong>Related information</strong><br />
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<div><a href="http://www-1.ibm.com/servers/eserver/iseries/optical/performance/optperfc.htm" target="_blank">Performance considerations</a></div>
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</div>
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</div>
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<img src="./deltaend.gif" alt="End of change" /></body>
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</html>
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