The SCDWGroomingSettings tool is a UI based, UNSUPPORTED tool to allow changes to the groom retention days within the SystemCenterReporting database.
From the Readme accompanying this download
SCDWGroomsettings is an unsupported utility that will allow modification of the groom retention days for the System Center Reporting database via a UI.
Use the Connect menu option to connect to the database server hosting the SystemCenterReporting database. Once connected, the default view will list each Fact table, the currently oldest data within that table, and the current retention days setting (defaults to 395 days when MOM Reporting is installed).
You are able to mouse click within the Retention days column and change the individual retention days for each Fact table. Therefore, if you have a requirement to store Samplenumericdata (performance data) less than 395 days, you can reduce the Retention days setting to a lower value.
NOTE: Attempting to reduce the Retention days value significantly lower than the Current oldest data value will trigger a dialog when you attempt to apply the change. The dialog is a warning about the consumption of transaction log that may occur during the grooming process. Attempting to reduce the retention days in one large single increment below the current oldest data is not recommended.
For example: Current oldest data in days=200, Retention days=395. You then change retention days to 90. The MOM SCDW grooming procedure will then have to groom 110 days worth of data from the database. The grooming is transactional and will therefore require a substantial sized transaction log.
Recommendation: When requiring to reduce the retention days substantially, reduce the value in small increments. Let the SCDWGroomjob run its natural course, or run it manually to remove the data from the systemCenterReporting database. Use the Connect menu option from the SCDWGroomsettings tool to refresh the Current oldest data and Retention days values.
Sorry I messed up my previous post. The download link is now working.