I have a sneaking suspicion this may be due to how full my drives are (11x5TB with 200-500GB free on each) but it does't exactly square with the fact that my downloads share is on the cache drive. When Nzbget is unpacking the downloaded files other applications will freeze up, specifically Plex. I'll be watching something on my Raspberry Pi 2 (RasPlex) and then it will freeze a little after the unrar starts and then become responsive again after it's finished. I'm almost certain I didn't alway have this issue which is why I lean towards a drive space issue and when I last ran into this I had space elsewhere to move stuff off to and I feel like it cleared up for a while. I also thought it might be Nzbget stealing all the CPU so I limited that docker image to only half my cores but that didn't help either and since I'm using the RPi2 I'm pretty much direct playing everything so CPU shouldn't be an issue.

 

I just wanted to see if anyone else has run into this and if there is anything I can do so that Nzbget doesn't halt my server when it's unpacking.

 

Thanks!

What filesystem are on your drives? RFS (Reiser) is known to really slow things down when ita nearly full.

 

I run XFS and do not have slowdown issues.

XFS on all my array drives and btrfs on my cache drives

Sounds more like you're CPU starved and/or bandwidth starved for disk IO.  Another possibility is that some disk controllers wind up pausing all other active connections to other attached disks when it has to spin up a disk

CPU starvation was my thought as well but limiting the nzbget container to only 4 out of 8 cores didn't change anything. IO bandwidth is something that sounds closer to the issue but the unpack all happens on the cache SSD drive so I wouldn't expect that to kill performance on the array. Also I'm not aware of a good tool to track down the IO culprit. iotop comes to mind but I'm not very good with it.

I'm experiencing the same issue with my server. Were you ever able to figure out the cause?