Another day, another update.
More troubleshooting was done today. What did we do:
- Yesterday evening @phiresky@phiresky@lemmy.world did some SQL troubleshooting with some of the lemmy.world admins. After that, phiresky submitted some PRs to github.
- @cetra3@lemmy.ml created a docker image containing 3PR's: Disable retry queue, Get follower Inbox Fix, Admin Index Fix
- We started using this image, and saw a big drop in CPU usage and disk load.
- We saw thousands of errors per minute in the nginx log for old clients trying to access the websockets (which were removed in 0.18), so we added a
return 404in nginx conf for/api/v3/ws. - We updated lemmy-ui from RC7 to RC10 which fixed a lot, among which the issue with replying to DMs
- We found that the many 502-errors were caused by an issue in Lemmy/markdown-it.actix or whatever, causing nginx to temporarily mark an upstream to be dead. As a workaround we can either 1.) Only use 1 container or 2.) set ~~
proxy_next_upstream timeout;~~max_fails=5in nginx.
Currently we're running with 1 lemmy container, so the 502-errors are completely gone so far, and because of the fixes in the Lemmy code everything seems to be running smooth. If needed we could spin up a second lemmy container using the ~~proxy_next_upstream timeout;~~ max_fails=5 workaround but for now it seems to hold with 1.
Thanks to @phiresky@lemmy.world , @cetra3@lemmy.ml , @stanford@discuss.as200950.com, @db0@lemmy.dbzer0.com , @jelloeater85@lemmy.world , @TragicNotCute@lemmy.world for their help!
And not to forget, thanks to @nutomic@lemmy.ml and @dessalines@lemmy.ml for their continuing hard work on Lemmy!
And thank you all for your patience, we'll keep working on it!
Oh, and as bonus, an image (thanks Phiresky!) of the change in bandwidth after implementing the new Lemmy docker image with the PRs.
Edit So as soon as the US folks wake up (hi!) we seem to need the second Lemmy container for performance. So that's now started, and I noticed the proxy_next_upstream timeout setting didn't work (or I didn't set it properly) so I used max_fails=5 for each upstream, that does actually work.
Am I getting this correct: the whole lemmy.world instance run in one single container on one single host?
You'd be surprised at how much performance this kind of setup can squeeze off. Often the limitation is more on the DB/storage than network handling and processing power.
This. Most of the time, the bottleneck will be the database backend.
Curious if lemmy.world uses separate reader/writer instances.
Impressive if true!
if it runs this well on a single container, considering the amount of users it has, I fear the power it'd hold with more
Lemmy is built on an async work stealing runtime and you can get very large instances from Amazon and the like.
I'm sure the instance isn't massive but number of containers and a single "host" are not great indicators of efficiency.