69 lines
5.4 KiB
HTML
69 lines
5.4 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="concept" />
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<meta name="DC.Title" content="Data recovery after disk failures for distributed relational databases" />
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<meta name="abstract" content="Recovery is not possible for recently entered data if a disk failure occurs and all objects are not saved on tape or disk immediately before the failure. After previously saved objects are restored, the server is operational, but the database is not current." />
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<meta name="description" content="Recovery is not possible for recently entered data if a disk failure occurs and all objects are not saved on tape or disk immediately before the failure. After previously saved objects are restored, the server is operational, but the database is not current." />
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<meta name="DC.subject" content="database recovery, disk failures, recovery" />
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<meta name="keywords" content="database recovery, disk failures, recovery" />
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<meta name="DC.Relation" scheme="URI" content="rbal1recovsupp.htm" />
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<meta name="DC.Relation" scheme="URI" content="rbal1auxstore.htm" />
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<meta name="DC.Relation" scheme="URI" content="rbal1checksum.htm" />
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<meta name="DC.Relation" scheme="URI" content="rbal1mirrored.htm" />
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<meta name="DC.Relation" scheme="URI" content="../rzahg/rzahgbackup.htm" />
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<meta name="copyright" content="(C) Copyright IBM Corporation 1998, 2006" />
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<meta name="DC.Rights.Owner" content="(C) Copyright IBM Corporation 1998, 2006" />
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<meta name="DC.Format" content="XHTML" />
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<meta name="DC.Identifier" content="rbal1datarecov" />
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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>Data recovery after disk failures for distributed relational databases</title>
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</head>
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<body id="rbal1datarecov"><a name="rbal1datarecov"><!-- --></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">Data recovery after disk failures for distributed relational databases</h1>
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<div><p>Recovery is not possible for recently entered data if a disk failure
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occurs and all objects are not saved on tape or disk immediately before the
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failure. After previously saved objects are restored, the server is operational,
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but the database is not current.</p>
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<p>Auxiliary storage pools (ASPs), checksum protection, and mirrored protection
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are <span class="keyword">i5/OS™</span> disk recovery
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functions that provide methods to recover recently entered data after a disk-related
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failure. These functions use additional server resources, but provide a high
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level of protection for servers in a distributed relational database. Because
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some servers might be more critical as application servers than others, the
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distributed relational database administrator should review how these disk
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data protection methods can be best used by individual servers
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within the network.</p>
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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="rbal1auxstore.htm">Auxiliary storage pools</a></strong><br />
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An auxiliary storage pool (ASP) is one or more physical disk units assigned to the same storage area. ASPs allow you to isolate certain types of objects on specified physical disk units.</li>
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<li class="ulchildlink"><strong><a href="rbal1checksum.htm">Checksum protection in a distributed relational database</a></strong><br />
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Checksum protection guards against data loss on any disk in an auxiliary storage pool (ASP).</li>
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<li class="ulchildlink"><strong><a href="rbal1mirrored.htm">Mirrored protection for a distributed relational database</a></strong><br />
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Mirrored protection increases the availability of a server by duplicating different disk-related hardware components, such as a disk controller, a disk I/O processor, or a bus. The server can remain available after a failure, and service for the failed hardware components can be scheduled at a convenient time.</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="rbal1recovsupp.htm" title="Failures that can occur on a computer server are a server failure (when the entire server is not operating); a loss of the site due to fire, flood, or similar catastrophe; or the damage or loss of an object. For a distributed relational database, a failure on one server in the network prevents users across the entire network from accessing the relational database on that server.">Recovery support for a distributed relational database</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="../rzahg/rzahgbackup.htm">Backup and recovery</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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