53 lines
2.9 KiB
HTML
53 lines
2.9 KiB
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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<meta name="DC.Title" content="Bus-level protection" />
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<title>Bus-level protection</title>
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</head>
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<body id="hdrlopbus"><a name="hdrlopbus"><!-- --></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">Bus-level protection</h1>
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<div><div class="fignone"><p>Determine if you want Bus-level protection based on the following: </p>
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<ul><li>Bus failures are rare in comparison to other disk-related hardware failures.</li>
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<li>The system can continue to operate after a bus failure. </li>
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<li>The system cannot operate if bus 1 fails.</li>
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<li>If a bus fails, disk I/O operations may continue, but other hardware is
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lost (such as work stations, printers and communication lines) making the
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system unusable.</li>
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<li><a href="rzalycmaintdef.htm">Concurrent
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maintenance</a> is not possible for bus failures.</li>
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</ul>
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<p>To achieve bus-level protection, all disk units that are attached to a
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bus must have a mirrored unit attached to a different bus. Bus-level protection
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is not possible for unit 1.</p>
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<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
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that contains two buses attached to separate IOPs, IOAs, and disk units, respectively.
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The two storage units make a mirrored pair. </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="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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