How to: Set the History Retention Period (SQL Server Management Studio)
Specify the history retention period on the General page of the Distribution Database Properties - <DistributionDatabase> dialog box. This setting controls how long replication agent history is stored. This page is available from the General page of the Distributor Properties - <Distributor> dialog box. For more information about accessing this dialog box, see How to: View and Modify Distributor Properties (SQL Server Management Studio).