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	<title>PerformanceWiki [the blog]</title>
	<link>http://performancewiki.com/wordpress</link>
	<description>performance tuning tips: quick &#038; to the point.</description>
	<pubDate>Wed, 23 Jan 2008 00:29:48 +0000</pubDate>
	<generator>http://wordpress.org/?v=2.0.5</generator>
	<language>en</language>
			<item>
		<title>IO Stack [PIC]</title>
		<link>http://performancewiki.com/wordpress/main/io-stack-pic</link>
		<comments>http://performancewiki.com/wordpress/main/io-stack-pic#comments</comments>
		<pubDate>Wed, 23 Jan 2008 00:29:48 +0000</pubDate>
		<dc:creator>info</dc:creator>
		
		<category>hardware setup</category>

		<category>oracle</category>

		<category>ibm db2</category>

		<category>Back-of-the-Envelope</category>

		<category>Database</category>

		<category>Storage</category>

		<category>Design</category>

		<category>Fibre Channel</category>

		<category>Capacity planning</category>

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	<category>scsi</category>
	<category>switch</category>
	<category>fibre</category>
	<category>controller</category>
	<category>driver</category>
	<category>routers</category>
	<category>multipath</category>
	<category>iscsi</category>
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		<guid isPermaLink="false">http://performancewiki.com/wordpress/main/io-stack-pic</guid>
		<description><![CDATA[I/O stack components Overview

Typically the stack consists of the following
• Database
• Character or block device driver
• Multipathing driver
• SCSI driver
• HBA
• System Bus
• Switch/iSCSI routers
• Storage Array
• Disks
Example of vendors:
ASM-Database IBM Oracle
Character or block device driver
Multipathing driver – PowerPath, Windows MPIO
SCSI driver
HBA – Host Bus Adapter, Qlogic (IBM), Emulex
System Bus - PCI
Switch/iSCSI routers – Brocade, [...]]]></description>
		<wfw:commentRss>http://performancewiki.com/wordpress/main/io-stack-pic/feed/</wfw:commentRss>
		</item>
		<item>
		<title>Oracle Query to Determine IO Imposed by Reports or Users</title>
		<link>http://performancewiki.com/wordpress/main/oracle-query-to-determine-io-imposed-by-reports-or-users</link>
		<comments>http://performancewiki.com/wordpress/main/oracle-query-to-determine-io-imposed-by-reports-or-users#comments</comments>
		<pubDate>Wed, 23 Jan 2008 00:10:50 +0000</pubDate>
		<dc:creator>info</dc:creator>
		
		<category>oracle</category>

		<category>Back-of-the-Envelope</category>

		<category>Storage</category>

		<category>Design</category>

		<category>Capacity planning</category>

	<!-- AutoMeta Start -->
	<category>imposed</category>
	<category>statistic</category>
	<category>extra</category>
	<category>sesstat</category>
	<category>substr</category>
	<category>assist</category>
	<category>statname</category>
	<category>userenv</category>
	<!-- AutoMeta End -->
	
		<guid isPermaLink="false">http://performancewiki.com/wordpress/main/oracle-query-to-determine-io-imposed-by-reports-or-users</guid>
		<description><![CDATA[Don&#8217;t forget to add extra IO imposed by users of the database. For example, to determine how much extra I/O will be imposed on the system when the new load is put into place. For example, if more users or reports will be added, determine how much I/O these reports (or a typical user) currently [...]]]></description>
		<wfw:commentRss>http://performancewiki.com/wordpress/main/oracle-query-to-determine-io-imposed-by-reports-or-users/feed/</wfw:commentRss>
		</item>
		<item>
		<title>IO Characteristics of Your Application</title>
		<link>http://performancewiki.com/wordpress/main/io-characteristics-of-your-application</link>
		<comments>http://performancewiki.com/wordpress/main/io-characteristics-of-your-application#comments</comments>
		<pubDate>Wed, 23 Jan 2008 00:01:40 +0000</pubDate>
		<dc:creator>info</dc:creator>
		
		<category>oracle</category>

		<category>Back-of-the-Envelope</category>

		<category>Database</category>

		<category>Design</category>

		<category>Capacity planning</category>

	<!-- AutoMeta Start -->
	<category>iops</category>
	<category>transaction</category>
	<category>requests”</category>
	<category>achievable</category>
	<category>extrapolate</category>
	<category>mbytes</category>
	<category>gigabytes</category>
	<category>bytes”</category>
	<!-- AutoMeta End -->
	
		<guid isPermaLink="false">http://performancewiki.com/wordpress/main/io-characteristics-of-your-application</guid>
		<description><![CDATA[IO rate of 1+ Gigabytes/sec is rarely achievable, but hundreds of Megabytes/sec is achieved in lots of high-end production environment. Keep those numbers in mind when planning for what&#8217;s possible.
In Oracle, use AWR reports to determine current I/O metrics (Instance Activity Stats per sec).
• IOPS = “physical reads total I/O requests” + “physical writes total [...]]]></description>
		<wfw:commentRss>http://performancewiki.com/wordpress/main/io-characteristics-of-your-application/feed/</wfw:commentRss>
		</item>
		<item>
		<title>2 Gigabit Card - How fast is it?</title>
		<link>http://performancewiki.com/wordpress/main/2-gigabit-card-how-fast-is-it</link>
		<comments>http://performancewiki.com/wordpress/main/2-gigabit-card-how-fast-is-it#comments</comments>
		<pubDate>Tue, 22 Jan 2008 23:40:13 +0000</pubDate>
		<dc:creator>info</dc:creator>
		
		<category>Back-of-the-Envelope</category>

		<category>Database</category>

		<category>Storage</category>

		<category>Design</category>

		<category>Fibre Channel</category>

		<category>Capacity planning</category>

	<!-- AutoMeta Start -->
	<category>bits</category>
	<category>misunderstanding</category>
	<category>hbas</category>
	<category>2gbits</category>
	<category>measurement</category>
	<category>sizing</category>
	<category>gigabit</category>
	<category>context</category>
	<!-- AutoMeta End -->
	
		<guid isPermaLink="false">http://performancewiki.com/wordpress/main/2-gigabit-card-how-fast-is-it</guid>
		<description><![CDATA[Common misunderstandings:
“If I buy 2 Gigabit HBAs I will get 2 Gigabytes of throughput, that’s more than enough throughput for my 400 MB/s application”
“I only need 2 disks to store my 1 TB database, now that we have 500GB disk drives are available!”
The first misunderstanding is not just about bits vs bytes, its understanding the [...]]]></description>
		<wfw:commentRss>http://performancewiki.com/wordpress/main/2-gigabit-card-how-fast-is-it/feed/</wfw:commentRss>
		</item>
		<item>
		<title>IOPS vs. Mbytes/sec</title>
		<link>http://performancewiki.com/wordpress/main/iops-vs-mbytessec</link>
		<comments>http://performancewiki.com/wordpress/main/iops-vs-mbytessec#comments</comments>
		<pubDate>Tue, 22 Jan 2008 23:24:28 +0000</pubDate>
		<dc:creator>info</dc:creator>
		
		<category>oracle</category>

		<category>Back-of-the-Envelope</category>

		<category>Database</category>

		<category>Storage</category>

		<category>Design</category>

	<!-- AutoMeta Start -->
	<category>metric_name</category>
	<category>snap_id</category>
	<category>mega”bytes”</category>
	<category>rate</category>
	<category>describe</category>
	<category>driven</category>
	<category>iops</category>
	<category>mbytes</category>
	<!-- AutoMeta End -->
	
		<guid isPermaLink="false">http://performancewiki.com/wordpress/main/iops-vs-mbytessec</guid>
		<description><![CDATA[IOPS

• The standard unit of measurement for I/O operations per second.
Includes all reads and writes.
• This is how you rate a I/O stack components ability to process small
block random I/O requests.
• Used to describe I/O rate driven applications (OLTP, random I/O )
Mbytes/s

• Mega”Bytes” per sec
• Used to measure large block sequential transfer rates, with no
response [...]]]></description>
		<wfw:commentRss>http://performancewiki.com/wordpress/main/iops-vs-mbytessec/feed/</wfw:commentRss>
		</item>
		<item>
		<title>Performance Definition: throughput</title>
		<link>http://performancewiki.com/wordpress/main/performance-definition-throughput</link>
		<comments>http://performancewiki.com/wordpress/main/performance-definition-throughput#comments</comments>
		<pubDate>Tue, 22 Jan 2008 23:12:37 +0000</pubDate>
		<dc:creator>info</dc:creator>
		
		<category>Back-of-the-Envelope</category>

		<category>Database</category>

		<category>Storage</category>

		<category>Design</category>

		<category>Fibre Channel</category>

	<!-- AutoMeta Start -->
	<category>definition</category>
	<category>factors</category>
	<category>bandwidth</category>
	<category>media</category>
	<category>transfer</category>
	<category>path</category>
	<category>discussing</category>
	<category>thought</category>
	<!-- AutoMeta End -->
	
		<guid isPermaLink="false">http://performancewiki.com/wordpress/main/performance-definition-throughput</guid>
		<description><![CDATA[Saw this definition from one of the Oracle OpenWorld sessions, thought it was pretty clear and concise:
Throughput

The measure of the transfer of bits across the media over a given period of time. Commonly used in discussing data transfer rates
Due to a number of factors, throughput usually does not match the specified bandwidth. Factors include:


The amount [...]]]></description>
		<wfw:commentRss>http://performancewiki.com/wordpress/main/performance-definition-throughput/feed/</wfw:commentRss>
		</item>
		<item>
		<title>Tuning Linux systems for WebSphere Application Server 6.0.x</title>
		<link>http://performancewiki.com/wordpress/main/tuning-linux-systems-for-websphere-application-server-60x</link>
		<comments>http://performancewiki.com/wordpress/main/tuning-linux-systems-for-websphere-application-server-60x#comments</comments>
		<pubDate>Fri, 11 Jan 2008 01:42:43 +0000</pubDate>
		<dc:creator>info</dc:creator>
		
		<category>app server tuning</category>

		<category>hardware setup</category>

		<category>linux</category>

		<category>file systems</category>

		<category>websphere 6.0.x</category>

	<!-- AutoMeta Start -->
	<category>sles</category>
	<category>2300mb</category>
	<category>suse</category>
	<category>redhat</category>
	<category>8000</category>
	<category>2511724800</category>
	<category>sp2a</category>
	<category>issuing</category>
	<!-- AutoMeta End -->
	
		<guid isPermaLink="false">http://performancewiki.com/wordpress/main/tuning-linux-systems-for-websphere-application-server-60x</guid>
		<description><![CDATA[When you have a performance concern, check the operating system settings to determine if these settings are appropriate for your application. Because the Linux operating system is not a WebSphere Application Server product, be aware that it can change and results can vary.
Procedure
Configure the following settings and variables according to your tuning needs:

timeout_timewait parameter

Description: Determines [...]]]></description>
		<wfw:commentRss>http://performancewiki.com/wordpress/main/tuning-linux-systems-for-websphere-application-server-60x/feed/</wfw:commentRss>
		</item>
		<item>
		<title>Tuning Windows systems for WebSphere Application Server 6.0.x</title>
		<link>http://performancewiki.com/wordpress/main/tuning-windows-systems-for-websphere-application-server-60x</link>
		<comments>http://performancewiki.com/wordpress/main/tuning-windows-systems-for-websphere-application-server-60x#comments</comments>
		<pubDate>Fri, 11 Jan 2008 01:37:50 +0000</pubDate>
		<dc:creator>info</dc:creator>
		
		<category>windows</category>

		<category>websphere 6.0.x</category>

	<!-- AutoMeta Start -->
	<category>regedit</category>
	<category>reg_dword</category>
	<category>registry</category>
	<category>subkey</category>
	<category>dword</category>
	<category>decimal</category>
	<category>incoming</category>
	<category>acknowledge</category>
	<!-- AutoMeta End -->
	
		<guid isPermaLink="false">http://performancewiki.com/wordpress/main/tuning-windows-systems-for-websphere-application-server-60x</guid>
		<description><![CDATA[IBM describes how to tune Windows 2000, Windows XP, and Windows 2003 operating systems to optimize the performance of WebSphere Application Server. Because Windows operating systems are not WebSphere Application Server products, be aware that the products can change and results can vary.
Procedure
Configure the following settings or variables according to your specific tuning needs:

TcpTimedWaitDelay

Description: Determines [...]]]></description>
		<wfw:commentRss>http://performancewiki.com/wordpress/main/tuning-windows-systems-for-websphere-application-server-60x/feed/</wfw:commentRss>
		</item>
		<item>
		<title>Tuning AIX systems for WebSphere Application Server 6.0.x</title>
		<link>http://performancewiki.com/wordpress/main/tuning-aix-systems-for-websphere-application-server-60x</link>
		<comments>http://performancewiki.com/wordpress/main/tuning-aix-systems-for-websphere-application-server-60x#comments</comments>
		<pubDate>Fri, 11 Jan 2008 01:28:30 +0000</pubDate>
		<dc:creator>info</dc:creator>
		
		<category>os tuning</category>

		<category>performance monitoring</category>

		<category>aix</category>

		<category>file systems</category>

		<category>websphere 6.0.x</category>

	<!-- AutoMeta Start -->
	<category></category>
	<!-- AutoMeta End -->
	
		<guid isPermaLink="false">http://performancewiki.com/wordpress/main/tuning-aix-systems-for-websphere-application-server-60x</guid>
		<description><![CDATA[IBM recommends a number of configuration changes and variables you can set to tune the performance of Websphere to suit your needs. Because the AIX operating system is not a WebSphere Application Server product, be aware that it can change and results can vary.
Procedure
Change the following configuration settings or variables according to your needs:

TCP_TIMEWAIT

Description: Determines [...]]]></description>
		<wfw:commentRss>http://performancewiki.com/wordpress/main/tuning-aix-systems-for-websphere-application-server-60x/feed/</wfw:commentRss>
		</item>
		<item>
		<title>Log SAR output to a file for later replay / analysis</title>
		<link>http://performancewiki.com/wordpress/main/log-sar-output-to-a-file-for-later-replay-analysis</link>
		<comments>http://performancewiki.com/wordpress/main/log-sar-output-to-a-file-for-later-replay-analysis#comments</comments>
		<pubDate>Tue, 02 Oct 2007 00:26:30 +0000</pubDate>
		<dc:creator>info</dc:creator>
		
		<category>performance monitoring</category>

		<category>automation</category>

		<category>linux</category>

	<!-- AutoMeta Start -->
	<category>sadc</category>
	<category>sadc</category>
	<category>outfile</category>
	<category>machine1</category>
	<category>average</category>
	<category>iface</category>
	<category></category>
	<category></category>
	<category>tps</category>
	<category></category>
	<category></category>
	<category></category>
	<category></category>
	<category></category>
	<category>ldavg</category>
	<!-- AutoMeta End -->
	
		<guid isPermaLink="false">http://performancewiki.com/wordpress/main/log-sar-output-to-a-file-for-later-replay-analysis</guid>
		<description><![CDATA[Commands below are for Linux, but the idea works everywhere &#8217;sadc&#8217; is available.
1) Start
/usr/lib/sa/sadc
Example
machine1:~ # /usr/lib/sa/sadc 2 7200 sadc.outfile
this logs SAR data for 4 hours.
2) Stop logging, do
&#8216;killall sadc&#8217; or &#8216;kill&#8217;
3) Usage of sar. Creating report with all options
sar -A -f
Example
machine1:~ # sar -A -f sadc.outfile > sar.outfile
machine1:~ # cat sar.outfile
Linux 2.4.21-75-default (machine1)   [...]]]></description>
		<wfw:commentRss>http://performancewiki.com/wordpress/main/log-sar-output-to-a-file-for-later-replay-analysis/feed/</wfw:commentRss>
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