Topic Last Modified: 2005-11-18
The Microsoft® Exchange Server Analyzer Tool includes a performance data collection engine that is used to query performance counter objects on computers that are running Exchange 2000 Server or Exchange Server 2003. The performance data collection engine collects data from the Available MBytes performance counter of the Memory performance object to analyze performance data. If the Exchange Server Analyzer collects any data from the Available MBytes performance counter, the Exchange Server Analyzer displays information about the collected data as baseline information.
The Available MBytes performance counter shows the amount of physical memory in megabytes (MB) immediately available for allocation to a process or for system use. The amount of memory available is equal to the sum of memory assigned to the standby (cached), free, and zero page lists.
By default, the Exchange Server Analyzer retrieves a sample every 30 seconds for a two-hour period. The Exchange Server Analyzer reports the maximum value for the performance counter during the collection interval. The Exchange Server Analyzer also reports the value that is at the ninetieth percentile of all collected values.
|If you list in ascending order all the values that the Exchange Server Analyzer collected, the ninetieth percentile is the value at the ninetieth percent position in the list. The ninetieth percentile value indicates the high values of this counter during the collection interval.|
In some instances, the maximum value will be the value at a peak point in the interval. Therefore the maximum value is not representative of the whole interval. The median value does not always accurately indicate load because the median value includes idle time during the collection interval. Therefore, the Exchange Server Analyzer reports the maximum value and the ninetieth percentile value.
The information in this baseline message is for information purposes only. There is no action required.
For more information about suggested thresholds of performance counters, see Troubleshooting Exchange Server 2003 Performance (http://go.microsoft.com/fwlink/?LinkId=47588).