89 lines
5.3 KiB
HTML
89 lines
5.3 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="Change parity set optimization" />
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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>Change parity set optimization</title>
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</head>
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<body id="rzalychgdpy"><a name="rzalychgdpy"><!-- --></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">Change parity set optimization</h1>
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<div><p>If you use a V5R2 input/output adapter (IOA) and OS/400<sup>®</sup> V5R2 or later, you can now choose
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how you want your parity sets to be optimized. When you select to optimize
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a parity set, the I/O adapter will choose disk units for parity sets according
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to the optimization value you have chosen. Depending on your configuration,
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different parity set optimizations might generate the same parity sets. You
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have several options for parity set optimization:</p>
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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="rzalydpy.htm">Work with device parity protection</a></div>
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</div>
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</div><div class="nested1" xml:lang="en-us" id="abailability"><a name="abailability"><!-- --></a><h2 class="topictitle2">Availability</h2>
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<div><p>A parity set optimized for availability offers a greater level of protection
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because it allows a parity set to remain functional in the event of a I/O
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bus failure. The availability optimization value ensures that a parity set
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is formed from at least three disk units of equal capacity each attached to
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a separate bus on the input/output adapter (IOA). For example, if an I/O adapter
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had 15 disk units and was optimized for availability, the result might be
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five parity sets with three disk units each attached to separate I/O buses
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on the adapter. OS/400 V5R3
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is required to optimize for availability.</p>
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</div>
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</div>
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<div class="nested1" xml:lang="en-us" id="capacity"><a name="capacity"><!-- --></a><h2 class="topictitle2">Capacity</h2>
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<div><p>A parity set optimized for capacity stores the most data possible. The
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I/O adapter may generate fewer parity sets with more disk units in each parity
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set. For example, if an I/O adapter has 15 disk units and is optimized for
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capacity, the result might be one parity set containing 15 disk units. </p>
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</div>
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</div>
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<div class="nested1" xml:lang="en-us" id="balanced"><a name="balanced"><!-- --></a><h2 class="topictitle2">Balanced</h2>
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<div><p>A balanced parity set compromises between the ability to store large amounts
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of data and also provide fast access to data. For example, if an I/O adapter
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has 15 disk units and you choose balanced parity optimization, the result
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might be two parity sets, one with nine disk units and one with six disk units.</p>
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</div>
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</div>
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<div class="nested1" xml:lang="en-us" id="performance"><a name="performance"><!-- --></a><h2 class="topictitle2">Performance</h2>
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<div><p>Parity sets optimized for performance provide the fastest data access.
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The I/O adapter may generate more parity sets with fewer numbers of disk units.
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For example, if an I/O adapter had 15 disk units and is optimized for performance,
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the result might be three parity sets with five disk units each.</p>
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</div>
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</div>
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<div class="nested1" xml:lang="en-us" id="change"><a name="change"><!-- --></a><h2 class="topictitle2">Steps to change parity set optimization</h2>
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<div><div class="p">To change the parity set optimization for all new parity sets that are
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created, use the following steps. This change stays in effect until you change
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it again. If you need to start parity, you can also change the parity set
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optimization as part of the start parity process.<ol><li> Expand <span class="uicontrol">Disk Units.</span></li>
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<li> Right-click <span class="uicontrol">Parity Sets</span> and select <span class="uicontrol">Change
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Optimization</span>.</li>
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</ol>
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</div>
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<div class="note"><span class="notetitle">Note:</span> RAID 6 protection gives you optimal performance, capacity,
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and balance, so selecting any of the parity set optimizations does not affect
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the outcome of the parity set.</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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