Subj : Re: Hub 3 Update
To   : deon
From : Zip
Date : Fri Apr 12 2024 09:50 pm

Hello deon!

On 12 Apr 2024, deon said the following...

 de> To be honest, I'm surprised that memory is the issue - docker stats show
 de> it using < 200MB of the 512MB that I had assigned to the DB, yet the
 de> kernel was killing it (oom-killer). I've doubled it just in case, but
 de> I'll need to keep an eye on it.

I think some of the default settings for memory/virtual memory in Linux leaves a lot to be desired, having vm.overcommit_memory = 0 (heuristic mode which tends to fail when an application wants lots of memory fast), vm.overcommit_ratio = 50 (only allow applications to use 50% of physical RAM) and vm.swappiness = 60 (rather high tendency to use swap).

Some good reads:

https://github.com/Tanzu-Solutions-Engineering/blog/blob/master/content/post/Vi
rtual_memory_settings_in_Linux_-_The_problem_with_Overcommit.md

https://unix.stackexchange.com/a/294651

https://en.wikipedia.org/wiki/Memory_paging#Swappiness

I have chosen to set vm.swappiness = 0, vm.overcommit_memory = 2 and vm.overcommit_ratio = 95 here to ensure that applications can use most of the amount of installed RAM and that swap is only used when really necessary.

Hope this helps!

Best regards
Zip

--- Mystic BBS v1.12 A49 2023/04/30 (Linux/64)
 * Origin: Star Collision BBS, Uppsala, Sweden (21:1/202)

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