Users are discussing unexpected daily backup growth (~0.2MB compressed, ~2MB uncompressed) on a new, nearly empty Discourse install with no new posts or uploads. me3 first noticed the steady increase and questioned if backups were backing up themselves — confirmed by zogstrip they are not. gerhard identified that system-generated private messages (PMs) for every automatic backup were contributing to growth, and committed a fix to send PMs only on errors or manual backups. codinghorror praised the improvement. schungx questioned if 1 PM could account for 2MB daily, suggesting user activity logs as another possible cause. gerhard noted in testing that backup logs added only ~75kB, and that other log tables may grow even without new posts. me3 offered to share backup files for inspection. Dannii shared a similar experience post-migration: initial rapid backup growth (~30MB/week) stabilized after ~3 months to 1-3MB/week, likely as logs reached equilibrium between new and expired data — reassuring others this is normal.
We’re not backing up the backups.
Is your forum active? Do you users upload images?
Just starting. No images yet.
It’s the DB growing by about 2MB / day which is about 0.2mb compressed.
Not a big problem, but interesting if the growth is continuous.
I think the backup logs are causing this. The system user creates a PM for every automatic backup, but it doesn’t invite the admins unless there was an error. I think it’s safe to create the PM only when there actually was an error or if it was a manual backup. I’m going to change that.
https://github.com/discourse/discourse/commit/0bc1fa8aa4ea5393193cc5c44adbf7eee24cd395
But one PM hardly generates 2MB of data each day. If the forum is being read by users, could it be the table holding the user activity logs?
I can upload the gz backups files somewhere if you like / want a look at them.
They aren’t particularly large yet.
It’s not a complaint. it’s a “that’s a strange steady growth rate” for a new nearly empty site.
I can’t attach files here or PM I don’t think.
In my tests the backup size increased roughly 75kB because of the backup logs. There are a bunch of log tables that could increase in size even though there are no new posts. Feel free to look at a diff of the database dump if you are curious, but I don’t think there’s anything else we can improve here.
After migrating to Discourse, I was concerned that our backups seemed to be increasing far more than expected. I was seeing backups increase by up to 30MB/week (after accounting for uploads) for only ~150 posts/week. But after about three months since migrating, the backups have stabilised to just 1-3MB/week. My guess would be that it took some logs some time to reach an equilibrium for new data vs expiring data. So if anyone else is in a similar situation after migrating, from my experience I’d say not to worry, it will eventually stabilise.
