To other Mastodon sysadmins: Check what pg_repack can do for you, especially if your server has been around for a really long time. PostgreSQL indexes get bloated over time and VACUUM does nothing about it. pg_repack can re-build indexes without downtime.
I shaved off 40 GB from the mastodon.social database just by using pg_repack on indexes tonight.
@Gargron How big are the database and media directories in total? What size of server is required to host a community like mastodon.social?
@Gargron Ah, so you're starting the year with a thorough cleaning of the house. Quite respectable.
@Gargron at work we have an intense INSERT/UPDATE’ activity on the core DB so we must rebuild indexes every week to ensure performance and mitigate storage waste.
@Gargron Next Hogmanay come for a ceilidh instead :)
Bliadhna Ur Mhath
@gargron "Eugen used this one weird trick to reduce the size of his PostgreSQL database by 40 GB! Hosting vendors hate him!!"
@Gargron
start the year off right, start the year’s mastodon off light
Server run by the main developers of the project 
It is not focused on any particular niche interest - everyone is welcome as long as you follow our code of conduct!
@Gargron
Thank you very much, you are the best