I have a post under docker wherein I stated that a docker app may be causing 100 % cpu utilization. Whenever I turn off the app, cpu goes back to normal. But there is one occasion wherein that app was off, and yet, I experienced the same problem.

 

Now I suspect that maybe no matter what docker app, so as long as memory is full, cpu utilization gets maxed out? Closing 1 app, actually lowers memory usage, hence, looks like closing that docker app fixes the problem. Can anyone confirm?

 

 

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That might happen, because file access to SSD/HDD take more time and that could stress the CPU more. (bc more concurrent actions) You really should set up your server so that it never runs out of memory (like closer limits to VM, Dockers and plugins), many bad things can happen if that happens. Also unraid has no protection against it, so even unraid fails without RAM.

Edited November 7, 20187 yr by nuhll

As my docker apps increases, this is the first time I'm experiencing this.  And I've got 3 systems that I'm managing, all coming up with the same symptoms.  At first, I thought it's the radarr container.  But now, I think it's due to lack of memory, and since all 3 systems are 8 GB and below, and using the same docker apps, I suspect this is the case now.  I have radarr, jackett, sonarr, and all these seems to take up quite a bit of memory relative to the other apps.

 

Will try increasing memory.  Thanks!

U can set limits on all of these apps, there are even apps (like cadvisor and netdata) where u can see which app takes the most. But ill suspect jacket and (if u use hydra) depending on how much indexers they use of using much RAM.

Edited November 7, 20187 yr by nuhll

Indeed, Jackett.  I also pinned radarr to a core, and yet, this didn't fix it.  Hence I began to suspect memory.  How do you set limit on apps?  Is that in advanced?  I don't use hydra just yet.  It's the same as Jackett, correct?

I wouldnt pin CPUs, for me this had only negative performance as  result.

 

Computers are nowadays relativly good in destribution the CPU power efficient by itself.

 

Normal the app should have somewhere a config option - or you need to change it in the config file itself. Or its a command line which u need to add to docker startup.

 

I couldnt find any informations about limit ram at jackett. U can limit ram for a docker via:

https://docs.docker.com/config/containers/resource_constraints/#understand-the-risks-of-running-out-of-memory

 

-m (megabyte)

 

Memory swap might also be an idea, but i suggest a SSD for it tho. (also higher CPU usage)

 

I also have relativly low RAM, what me helped was restarting all Dockers everyday (via backup plugin, nice sideeffect)

Edited November 7, 20187 yr by nuhll

Ok.  CPU pinning is my temporary problem elimination method.  But it seems clear memory is the culprit, I've got too less ram, and many apps using a lot or memory.  Will increase memory first and see how it goes.  Thanks @nuhll