Click Start, point to All Programs, point to Administrative Tools, and then click SharePoint Central Administration.
In the Component Configuration section, click Configure usage analysis processing.
In the Logging Settings section, select the Enable logging check box.
In the Log file location box, type the location in which to store the log file.
The default location for the log file is C:\WINDOWS\system32\logfiles\STS.
In the Number of log files to create box, type a number between 1 and 30.
In general, you should use a number that is one to three times the number of database servers in your server farm, with a maximum number of 30 log files.
In the Processing Settings section, select the Enable usage analysis processing check box.
Under Run processing between these times daily, in the Start box, select the earliest time of day that log processing can begin. In the End box, select the latest time of day that log processing can begin. Be sure to set an interval of at least 30 minutes for the start of usage processing.
