Exchange Database Test

This test measures the performance of the Exchange server database. The Exchange server database comprises of files with “.edb” and “.stm” extensions. A database is a collection of mailboxes. A pair of “.edb” and  “.stm” files makes a mailbox.

When an Internet mail message enters into the Exchange server, the body of the message is saved in the “.stm” file, and the header information (From, To, Cc, Time Sent, and so on) is converted to Rich Text Format (RTF), and then stored in the “.edb” file. The transaction log file maintains the state and integrity of “.edb” and “.stm” files.

Target of the test : An Exchange server 2000/2003

Agent deploying the test : An internal agent

Outputs of the test : One set of results for every Exchange server being monitored.

Configurable parameters for the test

Parameters	Description
Test Period	How often should the test be executed.
Host	The IP address of the machine where the Exchange Server is installed.
Port	The port number through which the Exchange server communicates. The default is 691.
IsPassive	If the value chosen is Yes, then the Exchange server under consideration is a passive server in an Exchange cluster. No alerts will be generated if the server is not running. Measures will be reported as "Not applicable" by the agent if the server is not up.

Measurements made by the test

Measurement	Description	Measurement Unit	Interpretation
Database cache hit ratio	This measure shows the percentage of database requests that were fulfilled by the database buffer pool without incurring disk input/output activity.	Percent	A significantly low value indicates that the Exchange server is not having enough free memory. Increasing the memory available to the server may solve this problem.
Database tables cache hit ratio	This measure shows the percentage of database tables opened using the cached schema information.	Percent	A significantly low value indicates that the Exchange server is not having enough free memory. Increasing the memory available to the server may solve this problem.
Log record waits	This measure shows the number of log records that cannot be added to the log buffers because the log buffers are full.	Records/Sec	This measure should be as close to zero as possible. Abnormal values of this metric indicate that the size of the log buffer is insufficient. The average value should be below 10 per second. Spikes (maximum values) should not be higher than 100 per second.
Log thread waits	This measure shows the number of threads waiting for their data to be written to the log buffer so that the update of the database can be completed.	Number	This measure should be as low as possible. A high value for this measure may indicate that the transaction log buffer might be a bottleneck.