I'm having a bit of an issue recently and I think I may have narrowed down when it happens - during heavy writes.
I'm using docker and VM's and when one of my dockers, sabnzbd is doing heavy writes to my drives I get a noticeable decline in overall server performance. The UI will become unresponsive, plex will hang, my cameras will go offline (haven't PROVED this, but the only time they go offline from the NVR is during writes - or so I suspect) The NVR is a Ubuntu VM on my unraid server.
Where should I start looking to improve this?
My server is a Dell R510 with 12 disks. 2 8TB parity disks, 1 256GB cache drive and 9 other misc hard drives.
Edit: Upon further inspection - I believe Sabnzbd is causing the issue. When a download completes, it starts to verify and unpack the download - and causes problems with the rest of the docker containers. I have tried to install another download client, like nzbget - but it says 6789 is in use - but it doesn't show it is anywhere.
I'll keep digging.