Compacting Tar Files As data is never overwritten in a tar file, the disk usage increases even when only updating existing data. To make up for the growing size of the repository, AEM employs a garbage collection mechanism called Tar Compaction. The mechanism will reclaim disk space by removing obsolete data from the repository. Revision Clean Up By default, tar file compaction is automatically run each night between 2 am and 5 am. The automatic compaction can be triggered manually in the Operations Dashboard via a maintenance job called Revision Clean Up. To start Revision Clean Up you need to: Go to the AEM Welcome Screen. In the main AEM window, go to Tools - Operations - Dashboard - Maintenance or directly browse to http://localhost:4502/libs/granite/operations/content/maintenance.html Click on Daily Maintenance Window. Hover over the Revision Clean Up window and press the Start button. The icon will turn orange to indicate that the Revision Clean Up