Ram suggestion for first server as Plex media Server and Mineos Host

[Rookie2222]

Just built my first server from new and old parts (old cpu, ram, mobo,) to be set up as a plex media server for my family (max 3 Concurrent Streams) and a Minecraft Server for friends (Max 8 people at a time).

Its going great so far and I'm enjoying playing with a not windows os but I am getting a little worried about my ram amount.

Current Relevant Specs:
CPU - 4770k
Ram - 16gb ddr3 1600 non-ecc
Storage - 4*4gb raid z1

Now my issue is without the minecraft server (running in mineos) the ram "usage" in the dashboard hovers between 5 - 6 gb for services leaving zfs cache 9 gb in some cases. This made me wary of the 1gb rule but as its not hard and fast I didn't worry too much.

Now with the minecraft server as well services sits at 9gb and zfs cache at 6.6gb

If I want to maintain this setup should I invest in 32gb of ram (I can't find any or my current sticks so would have to buy a full new set). If more ram is required I would prefer this option over putting minecraft and the other services on a new separate server like some may suggest as ram will likely be far cheaper even if it isn't necessarily what TrueNAS is designed for.

I do appreciate any suggestions in any direction though as this is my first go at this kind of stuff and I could be getting something completely wrong.

PS minecraft stuff: had heap size at 1024 and java used like 3gb of memory but got some lighting glitches and a crash so changed it to 2048 and its now using 4gb

 

[jgreco]

Basically the way this works is that you take the RAM you have, and subtract the RAM your jails/services are using, and that's the amount of RAM you have for ZFS purposes, which is where the ZFS ARC sizing rules come from.

So if you "have" 16GB but your Minecraft is using 4GB, and Plex might use 2GB-4GB (this is dependent on many factors including library size), you might really only have the bare minimum 8GB TrueNAS needs to work. This works out similarly to the 9GB you've measured for services.

This is not necessarily catastrophic, but it is probably subpar. If you're happy with how it is working, then that's fine, but do expect that you're much closer to the "end of potential growth" than you are to the beginning. It would not be harmful to add another 8GB or 16GB of RAM.

 

[Rookie2222]

Thanks for the prompt reply jgreco, I appreciate it. I'll look into my ram expansion options if I notice any more issues or just to be safe.

 

[Jurgen Segaert]

Yeah, good call! The 2048MB of heap is unfortunately becoming the minimum nowadays; Minecraft servers are big memory hogs.