Hello everyone, I have been running an instance of Discourse for the last 2 years with Digital Ocean without any problem but since the last 2 weeks, it became very slow or unavailable most of the time. I have upgraded my hosting to the following one, it’s a bit better but still facing the same pro…

top - 04:41:15 up 1 day, 25 min, 1 user, load average: 6.32, 7.70, 6.89 Tasks: 162 total, 4 running, 158 sleeping, 0 stopped, 0 zombie %Cpu(s): 64.2 us, 19.9 sy, 0.0 ni, 6.9 id, 7.7 wa, 0.0 hi, 1.3 si, 0.0 st KiB Mem : 4048268 total, 116444 free, 2742964 used, 1188860 buff/cache K…

Given the 1m load average is nearly half what it was in the previous screenshot, and %iowait is still pretty high, I’d say you’re probably I/O constrained, likely due to swapping. Confirm with sar -W 1 whilst the system is at peak unhappiness, and then upgrade RAM.

Thanks Matt, Here is the output of the sar -W 1 (I have no idea what it is :confused: ) 04:52:49 AM pswpin/s pswpout/s 04:52:50 AM 95.00 2.00 04:52:51 AM 166.00 0.00 04:52:52 AM 40.00 0.00 04:52:53 AM 19.00 0.00 04:52:54 AM 74.00 0.00 04:52:55 AM 125…

The headings should give you a hint… “pages swapped in per second” and “pages swapped out per second”. Each page is (usually) 4k, so swapping in 1,000 pages in a second means you’re copying about 4MB of data off disk and into RAM. That’s gonna take a while. You’re definitely due for a RAM upgrade…

Running this many unicorn workers on two virtual cpus that already run redis and pg does not make sense. I would run 3 workers max, and give the leftover ram to postgres.

Thanks guys. What I don’t understand is that I had 2GB RAM and it was working well, then suddenly I started to have a high load average. I already upgraded to 4GB RAM and I am still facing the same issue, how is it possible that Discourse suddenly needs so much more RAM? I also changed my app.yml …

[image] JohnDoux: I also changed my app.yml with UNICORN_WORKERS: 3 , it was 8 before. let us know how you go with the safer number

[image] JohnDoux: how is it possible that Discourse suddenly needs so much more RAM? You probably started serving a whole lot more traffic.

[image] mpalmer: You probably started serving a whole lot more traffic. Well actually that’s pretty much the opposite :confused: It’s a lot more quiet during summer vacation. So after 2 hours and around 30 users live: top - 06:11:09 up 1 day, 1:55, 1 user, load average: 4.09, 3.24, 2.91 …

Discourse unavailable with high load average

Support

mpalmer (Matt Palmer) September 3, 2018, 8:38am 2

What’s the %iowait? In general, htop is a poor substitute for top for actual diagnostic purposes.

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Discourse unavailable with high load average

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