On my linux servers I usually set vm.swappiness to around 20 to reduce linux’s desire to swap from RAM to disk.
Even though TrueNAS is (now) based on linux, I know it’s essentially a custom distro, so I’m not sure if changing this setting would help or hurt. Especially I’m not sure how to might interact with ZFS ARC.
Any thoughts? Thanks.
Covered in at least E009 of TrueNAS Tech Talks
Swap has been disabled in SCALE/CE. This has completely solved all issues with the ARC, OOM, and crashes.[1]
Changing the vm.swappiness will not change anything. I would leave it alone. You’ll be fine.
The reason for earlier issues on SCALE in regards to ARC, OOM, and crashes was because swap was still a thing. Disabling it magically made TrueNAS SCALE/CE the most stable ZFS server in existence, especially when VMs and Apps are running. ↩︎
You know winnie, I’m not sure new users are used to your particular brand of sarcasm.
Swap is indeed now disabled though & while there is the occasional post of oom, I haven’t experienced it since swap was disabled & manually managing my arc size & memory limits for all vms & apps.
That may well be, but I’m not a new user, and am used to winnie’s sarcasm. 
Is the official position of TrueNAS (formerly iXsystems) to manually manage ARC sizes and limits? 
My bad to imply either about you; for some reason I hallucinated the ‘first post/welcome’ banner. Statement stands though as warning to actual newbies.
God knows; I remember how excited I was when 50% limit was lifted. It is ironic that I’m more or less back to 50% limit willingly now.
