61 lines
3.7 KiB
HTML
61 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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<head>
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<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
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<meta name="DC.Type" content="topic" />
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<meta name="DC.Title" content="Details: Levels of protection" />
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<meta name="DC.Relation" scheme="URI" content="rzalymirror3.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.Identifier" content="hdrlopdet" />
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<!-- All rights reserved. Licensed Materials Property of IBM -->
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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>Details: Levels of protection</title>
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</head>
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<body id="hdrlopdet"><a name="hdrlopdet"><!-- --></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">Details: Levels of protection</h1>
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<div><p>The level of mirrored protection determines whether the system keeps running
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when different levels of hardware fail. Mirrored protection always provides
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disk-unit level protection, which keeps the system available for a single
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disk-unit failure. To keep the system available for failures of other disk-related
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hardware requires higher levels of protection. For example, to keep the system
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available when an I/O processor (IOP) fails, all of the disk units attached
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to the failing IOP must have mirrored units attached to different IOPs.</p>
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<p>The level of mirrored protection also determines whether <a href="rzalycmaintdef.htm">concurrent maintenance</a> can be done for different types
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of failures. Certain types of failures require concurrent maintenance to diagnose
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hardware levels above the failing hardware component. For example, to diagnose
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a power failure in a disk unit, you need to reset the I/O processor to which
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the failed disk unit is attached. Therefore, IOP-level protection is required.
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The higher the level of mirrored protection, the more often concurrent maintenance
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is possible.</p>
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<p>The level of protection you get depends on the hardware you duplicate.
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If you duplicate disk units, you have disk-unit level protection. If you duplicate
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IOAs as well, you have IOA-level protection. If you duplicate input/output
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processors, you have IOP-level protection. If you duplicate buses, you have
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bus-level protection. Mirrored units always have at least disk-unit level
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protection. </p>
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<p>During the start mirrored protection operation, the system pairs the disk
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units to provide the maximum level of protection for the system. When disk
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units are added to a mirrored disk pool, the system pairs only those disk
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units that are added without rearranging the existing pairs. The hardware
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configuration includes both the hardware and how the hardware is connected.</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="rzalymirror3.htm">Determine the level of protection that you want</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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