SABnzbd download speed substantially slower than on my old NAS

[prrtzt]

Hi community,

 

I just moved from a Synology DS718+ to an Unraid setup (Core i3-12100, 32GB DDR5, 2 x WD SN700 NVME in ZFS mirror for cache, 3 x Exos 20TB in the array).

 

I'm encountering some performance issues with SABnzbd and I can't figure out why. I have a 1 Gb/s Fiber connection. With my old Synology, downloads were stabilizing around 70-80 MB/s. Moving to a more powerful machine with SSD cache, I was expecting to go higher than that, but I'm only hitting around 50-55 MB/s with SABnzbd in Docker. 

 

The speed is consistent, whether I'm downloading an NZB or doing a test via the wrench icon. In theory, I should be maximizing my Gigabit connection with the setup I have. I have a Newshosting subscription with 100 connections (I tried to play with the number of connections and performance only goes down further). Again, my Synology with the exact same SABnzbd settings can hit 80 MB/s.

 

My downloads folder is in my media share, which is set as cache first. SABnzbd tells me the disk writing speed is around 1200 MB/s, which is consistent with the SSD cache. I have verified that the downloaded files are indeed in the cache volume.

 

I have tried setting up a new container from scratch, or using a different image, but the problem persists. I tried installing SABnzbd in a Windows VM and I'm hitting slightly higher speeds of around 65 MB/s (not great either, but I suspect this is just about VM read/write performance).

 

I have spent two hours researching this here and on Reddit but I can't find a solution. Help would be greatly appreciated :)

 

Thanks!

[JorgeB]

Is it faster if you map SABnzbd to a disk share or an exclusive share?

[prrtzt]

26 minutes ago, JorgeB said:

Is it faster if you map SABnzbd to a disk share or an exclusive share?

Thanks for the suggestion, just tried that. I set my appdata share as exclusive, and set a folder inside of that as the downloads folder for SABnzbd.

Unfortunately, the results are exactly the same.

 

What I also tried yesterday was to do a file transfer from my array to appdata from within a Windows VM, and I was getting 260 MB/s which is the maximum read speed of my spinning drives. So I really don't think disk IO is the issue.

[JorgeB]

If exclusive shares don't help it indicates to me it's not an Unraid specific issue, suggest asking in the container support thread/discord, there may be some known configuration issues.

[prrtzt]

9 minutes ago, JorgeB said:

If exclusive shares don't help it indicates to me it's not an Unraid specific issue, suggest asking in the container support thread/discord, there may be some known configuration issues.

Thanks, will do!