Enable external merge request diff storage
On GitLab.com, merge_request_diff_files
is the biggest table at about 1.1TB currently and it grows at a rate of about 60 GB per month.
We should look into enabling external merge request diff storage as pointed out below: https://docs.gitlab.com/ee/administration/merge_request_diffs.html
Update (2020-02-26):
The current size of the relevant table merge_request_diff_files
is 1,659 GB out of 5,400 GB total database size (about 30% of the total database size is this single table). Once the migration is done, all of this data should live outside the database and reduce the database size by 30%.