53 lines
2.9 KiB
HTML
53 lines
2.9 KiB
HTML
|
<?xml version="1.0" encoding="UTF-8"?>
|
||
|
|
<!DOCTYPE html
|
||
|
|
PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
|
||
|
|
<html lang="en-us" xml:lang="en-us">
|
||
|
|
<head>
|
||
|
|
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
|
||
|
|
<meta name="security" content="public" />
|
||
|
|
<meta name="Robots" content="index,follow" />
|
||
|
|
<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))' />
|
||
|
|
<meta name="DC.Type" content="topic" />
|
||
|
|
<meta name="DC.Title" content="Bus-level protection" />
|
||
|
|
<meta name="DC.Relation" scheme="URI" content="rzalymirror3.htm" />
|
||
|
|
<meta name="copyright" content="(C) Copyright IBM Corporation 2002, 2006" />
|
||
|
|
<meta name="DC.Rights.Owner" content="(C) Copyright IBM Corporation 2002, 2006" />
|
||
|
|
<meta name="DC.Format" content="XHTML" />
|
||
|
|
<meta name="DC.Identifier" content="hdrlopbus" />
|
||
|
|
<meta name="DC.Language" content="en-us" />
|
||
|
|
<!-- All rights reserved. Licensed Materials Property of IBM -->
|
||
|
|
<!-- US Government Users Restricted Rights -->
|
||
|
|
<!-- Use, duplication or disclosure restricted by -->
|
||
|
|
<!-- GSA ADP Schedule Contract with IBM Corp. -->
|
||
|
|
<link rel="stylesheet" type="text/css" href="./ibmdita.css" />
|
||
|
|
<link rel="stylesheet" type="text/css" href="./ic.css" />
|
||
|
|
<title>Bus-level protection</title>
|
||
|
|
</head>
|
||
|
|
<body id="hdrlopbus"><a name="hdrlopbus"><!-- --></a>
|
||
|
|
<!-- Java sync-link --><script language="Javascript" src="../rzahg/synch.js" type="text/javascript"></script>
|
||
|
|
<h1 class="topictitle1">Bus-level protection</h1>
|
||
|
|
<div><div class="fignone"><p>Determine if you want Bus-level protection based on the following: </p>
|
||
|
|
<ul><li>Bus failures are rare in comparison to other disk-related hardware failures.</li>
|
||
|
|
<li>The system can continue to operate after a bus failure. </li>
|
||
|
|
<li>The system cannot operate if bus 1 fails.</li>
|
||
|
|
<li>If a bus fails, disk I/O operations may continue, but other hardware is
|
||
|
|
lost (such as work stations, printers and communication lines) making the
|
||
|
|
system unusable.</li>
|
||
|
|
<li><a href="rzalycmaintdef.htm">Concurrent
|
||
|
|
maintenance</a> is not possible for bus failures.</li>
|
||
|
|
</ul>
|
||
|
|
<p>To achieve bus-level protection, all disk units that are attached to a
|
||
|
|
bus must have a mirrored unit attached to a different bus. Bus-level protection
|
||
|
|
is not possible for unit 1.</p>
|
||
|
|
<br /><img src="rzaix520.gif" alt="Figure showing the elements of bus-level protection" /><br /><p>This figure shows the elements of bus-level protection: one expansion unit
|
||
|
|
that contains two buses attached to separate IOPs, IOAs, and disk units, respectively.
|
||
|
|
The two storage units make a mirrored pair. </p>
|
||
|
|
</div>
|
||
|
|
</div>
|
||
|
|
<div>
|
||
|
|
<div class="familylinks">
|
||
|
|
<div class="parentlink"><strong>Parent topic:</strong> <a href="rzalymirror3.htm">Determine the level of protection that you want</a></div>
|
||
|
|
</div>
|
||
|
|
</div>
|
||
|
|
</body>
|
||
|
|
</html>
|