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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en"> <head> <meta http-equiv="Content-Type" content="text/html; charset=us-ascii" /> <meta http-equiv="Content-Style-Type" content="text/css" /> <meta http-equiv="Content-Script-Type" content="text/javascript" /> <title>Monitoring I/O by Type</title> <meta name="generator" content="Oracle DARB XHTML Converter (Mode = ohj/ohw) - Version 5.1.1 Build 005" /> <meta name="date" content="2009-05-27T15:13:1Z" /> <meta name="robots" content="noarchive" /> <meta name="doctitle" content="Monitoring I/O by Type" /> <meta name="relnum" content="11g Release 2 (11.2)" /> <meta name="partnum" content="E10822-01" /> <link rel="copyright" href="./dcommon/html/cpyr.htm" title="Copyright" type="text/html" /> <link rel="stylesheet" href="./dcommon/css/blafdoc.css" title="Oracle BLAFDoc" type="text/css" /> <link rel="contents" href="toc.htm" title="Contents" type="text/html" /> <link rel="prev" href="tdppt_realtime014.htm" title="Previous" type="text/html" /> <link rel="next" href="tdppt_realtime016.htm" title="Next" type="text/html" /> <script src="./callback.js" type="text/javascript"></script> <noscript>Your browser does not support JavaScript. This help page requires JavaScript to render correctly.</noscript> </head> <body> <div class="zz-skip-header"><a href="#BEGIN">Skip Headers</a></div> <table class="simple oac_no_warn" summary="" cellspacing="0" cellpadding="0" width="100%"> <col width="86%" /> <col width="*" /> <tr valign="bottom"> <td align="left"></td> <td align="center"><a href="tdppt_realtime014.htm"><img src="./dcommon/gifs/leftnav.gif" alt="Previous" /><br /> <span class="icon">Previous</span></a> </td> <td align="center"><a href="tdppt_realtime016.htm"><img src="./dcommon/gifs/rightnav.gif" alt="Next" /><br /> <span class="icon">Next</span></a></td> </tr> </table> <p><a id="CBBIHDHB" name="CBBIHDHB"></a><a id="TDPPT330" name="TDPPT330"></a></p> <div class="sect3"> <h1>Monitoring I/O by Type</h1> <a name="BEGIN" id="BEGIN"></a> <p>The I/O Type charts enable you to monitor I/O by the types of read and write operations. Small I/Os are requests smaller than 128 KB and are typically single database block I/O operations. Large I/Os are requests greater than or equal to 128 KB. Large reads are generated by database operations such as table/index scans, direct data loads, backups, restores, and archiving.</p> <p>If you are optimizing for low transaction times, then monitor the rate at which I/O requests are completed. Single-block performance is optimal when there is low I/O latency. High latencies typically indicate that the storage system is a bottleneck. Performance is negatively impacted by large I/O workloads.</p> <p>If you are optimizing for large queries, such as in a data warehouse, then performance is dependent on the maximum throughput your storage system can achieve rather than the latency of the I/O requests. In this case, monitor the I/O megabytes per second rather than the synchronous single-block read latencies.</p> <p class="orderedlisttitle">To monitor I/O by type: </p> <ol> <li> <p>From the Database Home page, click <span class="bold">Performance</span>.</p> <p>The Performance page appears.</p> </li> <li> <p>In the instance activity chart, click <span class="bold">I/O</span>.</p> <p>The I/O Megabytes per Second and I/O Requests per Second charts appear.</p> </li> <li> <p>For <span class="bold">I/O Breakdown</span>, select <span class="bold">I/O Type</span>.</p> <p>The I/O Megabytes per Second by I/O Type and I/O Requests per Second by I/O Type charts appear.</p> </li> <li> <p>Click the largest block on the chart or its corresponding function in the legend to drill down to the function with the highest I/O rate.</p> <p>The I/O Details page appears.</p> <p>You can view real-time or historical data for details on I/O megabytes or I/O requests.</p> </li> </ol> <div class="helpinfonotealso"> <h2>Related Topics</h2> <p><a href="tdppt_realtime013.htm#CBBIFFJE">Monitoring I/O</a></p> </div> </div> <!-- class="sect3" --> <!-- Start Footer --> <div class="footer"> <table class="simple oac_no_warn" summary="" cellspacing="0" cellpadding="0" width="100%"> <col width="86%" /> <col width="*" /> <tr> <td align="left"><span class="copyrightlogo">Copyright © 2007, 2009, Oracle and/or its affiliates. All rights reserved.</span><br /> <a href="./dcommon/html/cpyr.htm"><span class="copyrightlogo">Legal Notices</span></a></td> <td align="center"><a href="tdppt_realtime014.htm"><img src="./dcommon/gifs/leftnav.gif" alt="Previous" /><br /> <span class="icon">Previous</span></a> </td> <td align="center"><a href="tdppt_realtime016.htm"><img src="./dcommon/gifs/rightnav.gif" alt="Next" /><br /> <span class="icon">Next</span></a></td> </tr> </table> </div> <!-- class="footer" --> </body> </html>
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