Advice sought on Memory and Swap Performance

[scoobertronics]

Hi All,
First time post.
Just wanting to interpret this report
TrueNAS-13.0-U4
24Gb RAM (Non ECC)
Intel(R) Core(TM) i5-6400 CPU @ 2.70GHz
7GB storage

I think I know what I am seeing here, is that I have not had any swap usage for pretty much 18th Dec onward?
IS my interpretation correct and is that good/bad or does not matter?

Also if someone could explain or point me to a resource that explains the various types of memory usage, that would be awesome.
Everything is working fine, there is no issue with the system, but wondering if I can improve performance.

I know I am not on sever hardware.. but available cash dictates that.

Cheers
Scott

 

[mav@]

TrueNAS is tuned to not swap unless really has to. There must be something on the NAS that uses plenty of RAM, causing that swap and also so high numbers of Inactive memory. It should not be something in the base TrueNAS, so I wonder if you run any plugins/jails?

 

[scoobertronics]

Thanks for the reply
So the swap was used a lot up to the 6th Nov but not too much after that, that's how I read the graph?
I run one jail, a Plex media server and one Linux VM - 1 Core 8Gb RAM
Is there a way I can use more of the inactive memory?

 

[mav@]

One of known cases for pathological use of Inactive is applications doing big mmap() calls. Unfortunately FreeBSD can't balance between those and ZFS ARC -- the last always looses competition. But it should not cause swapping, system should still free mmap()'ed memory before that. I don't remember for sure, but I guess that the 8GB of VM RAM may also end up in Inactive if not regularly accessed -- that is how VM subsystem detects what it can swap-out.