Different Backup Server speeds in SAB and Newsleecher

[ALbino]

Hey guys,

Yesterday I ran into a situation where a file wasn't on any of my primary servers, but it was found on one of my backups, but it was downloading very slowly, around 250 kB/s (I have a 150 mbit connection and max out around 18.2 mB/s). I let it run for hours, but eventually gave up, and opened the same NZB in Newsleecher. It located the file on the same European backup server but instead I was now downloading at 5 mB/s.

Now again today I was downloading several NZBs in a series that are all missing from my primary servers, but were found on a backup server (a different one than the previous day, this time a US backup). Again it was stuck at around 250-500 kB/s. So I opened the NZB in Newsleecher, and it wasn't found on the primary, but was found on the same backup as SABnzbd found it, but now it was downloading at a solid 10 mB/s.

If I add another file to my queue that is found on the primary servers I get my full 18 mB/s. It is only when switching to the backup where it's going so slow, and it's not slow at all in Newsleecher.

I've been running SABnzbd for months without this problem, and the only thing I could think of is that I recently I added a few more backup servers to SABnzbd, so I thought maybe it was getting overwhelmed requesting from so many different ones, and disabled all of them except the one where the files were found, but that didn't help. I restarted SAB and then restarted my PC when that didn't work. I was thinking of just outright deleting the servers I added to see if that would fix it, but since they're currently disabled I don't think that should be the problem. Any advice would be appreciated. Thanks.

SABnzbd: 0.7.20
OS: Windows 7 Professional
Computer: Quadcore, 16gb of RAM

[ALbino]

I've been doing a bit more testing, and I've determined that it's related to the number of Primary Servers I have. If I disable every server except the one that was working then I get full speed. If I switch it between Backup and Primary it doesn't matter. If I enable 1 or 2 Primary servers and leave it as a Backup then everything is still full speed. But once I enable my full 5 Primary servers the speed drops like a rock. I'm attaching a screenshot, with the server isolated on the left, then pausing it and enabling the primaries on the right:

[shypike]

SABnzbd will first try all of your primary servers.
This takes time, especially when those servers are slow to respond to missing articles.
If you let Newsleecher download only from the backup server, of course it will be faster.

[ALbino]

I knew that was the case, but I didn't think the difference would be so dramatic. Thanks for the feedback!

[ALbino]

After doing more testing I've realized that the problem wasn't the number of primary or backup servers, the problem was that one of my primary servers was set to only 1 connection. Once I changed that server from 1 connection to 10 the speed from the backup server increased significantly.

I'm thinking that with only 1 connection enabled in the primary server, that allows only 1 failed article, which leads to 1 attempted connection on the backup server. Therefore even if you have 50 connections enabled in your backup server it won't matter because SAB is only attempting to fetch using 1 connection at a time. The reason disabling a primary server worked before is because I was disabling the primary that was set to only the 1 connection, and leaving the ones that had multiple connection active.

This makes sense to me, and obviously it was a quirk of my personal setup that I was only using 1 connection from one of my primary servers. I doubt it applies to many other people, but I thought it was worth mentioning in case anybody is ever having a similar problem and stumbles on this thread.

[shypike]

That's a sound analysis.