Near 100% Ram usage/reservation - normal?

[Iacov]

hey

i think it's normal (at least similar threads point in that direction) - but want to make sure, because my installation fresh and i don't want to miss a wrong configurations on my side

my jellyfin runs in docker (lsio image) on a ubuntu server 22.04 (HWE Stack) VM on Proxmox (with iGPU passthrough)
the VM has 8gb of memory (of 16gb total)

the "weird" behavior is:
as soon as the vm starts, nearly all of the RAM is being "taken" - proxmox displaying roughly 8 of 16gb being in use
the VM itself reports (in proxmox) a use of 2gb at the beginning - after a while (and being in use), the proxmox graph displays 7,5 of 8gb used (please see screenshot jellyram1)

on the other side, htop reports, if i read it correctly, that the ram is actually reserved, but only around 2gb are actually used
(please see screenshot jellyram2)

and while i'm writing this, htop displayed a drop of reserved (yellow) ram to around 60% (jellyram3) - insert confused-screaming-meme

i don't know why this is happening - is this ubuntu behaviour? is this a jellyfin quirk?
the vm neither crashes nor do i have playback issues apparently, so i "think" everything is fine - but am interested in your experience and assessment

thank you very much

[TheDreadPirate]

In your screenshots only ~2GB is ACTUALLY used/reserved. The rest is caching, which is normal. Unused memory is wasted memory and Linux will use a lot of memory for caching. Memory used for caching is easily released when another app needs it. A lot of UIs, like that Proxmox screenshot, do not differentiate between reserved memory (memory that is actually in use) and cache.