87 lines
5.5 KiB
HTML
87 lines
5.5 KiB
HTML
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<meta name="DC.Title" content="Restrictions and considerations for Extended Adaptive Cache" />
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<meta name="abstract" content="See what components Extended Adaptive Cache requires and learn more about what to expect." />
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<title>Restrictions and considerations for Extended Adaptive Cache</title>
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<body id="rzahxeacplan"><a name="rzahxeacplan"><!-- --></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">Restrictions and considerations for Extended Adaptive Cache</h1>
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<div><p>See what components Extended Adaptive Cache requires and learn
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more about what to expect.</p>
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<p>Before you begin using Extended Adaptive Cache, you should do some initial
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planning to take into account any restrictions or considerations that may
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pertain to your computing environment.</p>
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<div class="section"><h4 class="sectiontitle">Restrictions</h4><p>To use Extended Adaptive Cache, your
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system must have the following:</p>
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<ul><li>One or more storage I/O adapters that support Extended Adaptive Cache
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(CCIN 2780 for systems running V5R2 or later).</li>
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<li>Performance Tools for <span class="keyword">iSeries™</span> licensed
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program for viewing the reported information.</li>
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</ul>
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<p>Extended Adaptive Cache is automatically enabled on supported I/O
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adapters. There is no controlled on or off switch. Once the I/O adapter has
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been inserted into the subsystem, Extended Adaptive Cache is activated. It
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takes approximately an hour for Extended Adaptive Cache to monitor the data
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flow and populate the read cache memory. After an hour of running Extended
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Adaptive Cache, your system should show improved performance (depending on
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your current workload) and increased I/O throughput.</p>
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<p>There are no restrictions
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for using Extended Adaptive Cache with regard to device parity protection
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and mirrored protection for other disks under the I/O adapter. Finally, Extended
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Adaptive Cache is designed specifically to complement <span class="keyword">iSeries</span> Expert
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Cache, and may be used with or without it.</p>
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</div>
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<div class="section"><h4 class="sectiontitle">Considerations</h4><p>Using the Extended Adaptive Cache
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allows you to attain a significant decrease in I/O response time and increase
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in system I/O throughput in most environments. As is the general case with
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caches, the system configuration and workload influence the effectiveness
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of Extended Adaptive Cache. Extended Adaptive Cache performs at the storage
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subsystem level. It caches data for the set of disks that are within that
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specific subsystem. Therefore, it is logical to add Extended Adaptive Cache
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to the most active and performance-critical storage subsystems within the
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system. Extended Adaptive Cache is not considered a pre-fetch type cache and
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therefore will not interfere with the read-ahead capabilities in the disk.</p>
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<p>The
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larger the area of disk storage that is actively receiving I/O requests, the
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more selective Extended Adaptive Cache is about deciding when to bring new
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data into cache. This adaptive ability allows Extended Adaptive Cache to be
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effective on many workload types and sizes.</p>
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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="rzahxeac1.htm" title="Explore Extended Adaptive Cache. Find information about planning, restrictions, and important considerations before you begin to use this tool.">Extended Adaptive Cache Concepts</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="../rzalm/rzalmlvm.htm">Device parity protection</a></div>
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<div><a href="../rzaly/rzalymirrorconcept.htm">Mirrored protection</a></div>
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<div><a href="rzahxeacuse.htm" title="To start Extended Adaptive Cache and increase your system's performance, purchase the Read Cache Device.">Start Extended Adaptive Cache</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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