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[RESOLVED] Qbittorent-nox Raspberry Pi Download Slow Down

Posted: Fri Mar 09, 2018 10:26 pm
by Zongdang
I've been running qBittorrent-nox successfully for a month on a Raspberry Pi Zero using an old usb to ethernet adapter to download my favorite TV shows.  I use Openvpn to connect to Nordvpn and haven't had any problems with that either.  Last night my torrents slowed down to about a tenth of the speed I had been getting and I have not made any changes there at all.  Just as a point of reference I also have a desktop machine where I run qBittorent and Nordvpn to download other content and am not experiencing any slowdown there at all.  That tells me that my router is not the issue, my internet provider is probably not the issue, and Nordvpn is probably not the issue (they allow up to 5 simultaneous sign ons).  Just to clarify, I have also paused desktop downloads to see if there is any affect on the Pi downloads.  Nope... nada.

I have changed the Pi to point at several different Nordvpn servers which does not resolve the issue so I don't think it is Nordvpn throttling me.  After I noticed the problem I tried rebooting the Pi which did not make any difference.  I then upgraded Raspbian and the firmware which also made no difference.  I have tried running network speed tests from the PI but have not found a reliable way to see what my internet speeds are there (I am running headless so don't have access to graphical tools).  I don't see how it could be a qBittorrent but I thought I would start here to see if anyone else has experienced/solved a similar issue.

Is there a possibility of fragmentation on the SD Card and if so would that cause a speed problem?  I have deleted old torrents and files using qBittorent's interface.  I would think Linux takes care of any fragmentation on the fly but I don't know that for sure.  If not, is there a way to address that with some utility?  I'm grasping at straws here but again I'm not sure where to start looking.

Re: Qbittorent-nox Raspberry Pi Download Slow Down

Posted: Fri Mar 09, 2018 11:02 pm
by Switeck
1/10th of what speed?
Are you on 1 gigabit/second (or faster!) fiber optic line and qBT slowed down from 100+ MB/sec to only 10-20 MB/sec?
(That might be fragmentation.)

Or from 1 MB/sec to only 100 KB/sec?
(Is the Raspberry Pi Zero overheating or getting lots of networking errors?)

Re: Qbittorent-nox Raspberry Pi Download Slow Down

Posted: Fri Mar 09, 2018 11:56 pm
by Zongdang
Sorry, I guess I should have been a little more specific though at this point it is moot because I seem to have either found the resolution or at least a workaround.  As to the Pi overheating, no, haven't had that problem.

Not sure if this is the resolution but it seems to have solved the problem, though I don't understand why it was a problem in the first place.  As I am usually in a hurry to get my TV shows so I can watch them as soon as possible I set the Global Upload Speed as low as possible which normally increases my download speeds considerably.  While this may seem greedy I do make up for it when the downloads are complete and then set the Global Upload Speed at the maximum and upload to a ratio of 1 which is really pushing it due to the small amount of space available on my Pi's SD card.

Anyway, I had the Global Upload Speed set at 1KiB/s (again, I know it sounds greedy but I make up for it after the downloads have completed).  When I removed that limit the download speed zoomed up to what I have been accustomed to as normal.  I then changed the Global Upload Speed to 10KiB/s and eked more download speed gains out.  Maybe this behaviour is mentioned in the documentation or well known by the rest of the community but I was unaware until now.  Anyway, my issue is resolved and I'm once again a happy camper!  Thanks for responding.

Re: Qbittorent-nox Raspberry Pi Download Slow Down

Posted: Sat Mar 10, 2018 12:20 pm
by Switeck
BitTorrent has Tit-For-Tat (something-for-something) -- peers upload to peers that give them the most.
When there's lots of seeds, that doesn't matter because seeds don't download from peers anyway.

If you're uploading to a peer at <1 KB/sec it will automatically snub your ip address, after which it may refuse to upload to you even if it becomes a seed.
On torrents with very few seeds but lots of's a download speed killer.