media_retention - enhancement to provide more control over deletion.

[ajohns92a]

Enhance features to purge media regardless of when it was accessed last

Media retention limits are observed, as long as the file is not accessed. This is clearly stated here:

options control whether media will be purged if it has not been accessed in a given amount of time. Note that media is 'accessed' when loaded in a room in a client, or otherwise downloaded by a local or remote user.
https://matrix-org.github.io/synapse/latest/usage/configuration/config_documentation.html#media_retention

That's awesome. But as long as someone somewhere on some random federated server keeps hitting up the file, it will remain forever. Could an override be put in to delete media after a set period, regardless of when it was accessed last?
One caveat, it would need to not apply to Profile pictures and room profile pictures.

[reivilibre]

Out of interest, is this motivated by a real problem you're having?

It sounds like a reasonable option to have. (I'm not sure whether we currently have the ability to exempt profile pictures from deletion, though!)
Another compromise I can imagine is not treating a remote access in the same way as a local access, for recency purposes.

[ajohns92a]

Thanks for the response. The two issues I've encountered in the past pertain to space (Tight budget VPS implementations) and undesirable media.

If a mod is not on top of it, holidays, family reasons or what ever, it's nice to know that no matter what, it won't be around after X period.

Yes that's a good idea as well. Treat Local vs Remote differently. I've noticed that some will simply right click and get link - then that's plastered around other random message boards and every time opened in a browser by a member from an unrelated message board, the remote access is counted in the DB.