Introduced in GitLab 8.4.

Automatic housekeeping

GitLab automatically runs git gc and git repack on repositories after Git pushes. If needed you can change how often this happens, or to turn it off, go to Admin area > Settings (/admin/application_settings).

Manual housekeeping

The housekeeping function runs git gc (man page) on the current project Git repository.

git gc runs a number of housekeeping tasks, such as compressing file revisions (to reduce disk space and increase performance) and removing unreachable objects which may have been created from prior invocations of git add.

You can find this option under your [Project] > Edit Project.

Housekeeping settings