I had many gigs of attachments in the database, then moved to the filesystem plugin, it seems faster, but the database didn't crash, just took sightly longer.
You have a few extra steps to configure the filesystem version, there is a command line script that will change the backend for you for each ticket, then you must ensure cron runs as the webserver so the attachments are saved by the same user, otherwise you can't get them back out again.
You'll get errors if you delete the files and not the attachment database entries as well.