Sab downloads killing network performance [solved]

[TheAmorphous]

This is an odd one. Just in the last two or three days I've noticed my network crawling at random. I finally figured out that it only happens when Sab is actively downloading something (anything).

No settings have changed recently, either in Sab or on my router, with the exception of changing number of connections from 60 down to 10 to see if it would help. It did not. Currently I'm running 0.8.0 beta 1.

When Sab is downloading, gigabit wired HTPCs begin stuttering and buffering video and even MP3s. My tablet, which usually sees ~10ms pings and >60Mbps speeds in a speed test app, will get 600+ ms pings and 3-4Mbps transfers while Sab is downloading. The entire network, both wired and wireless becomes unusable. I've checked my router's performance page and both CPU and RAM usage are low when this is happening; nothing out of the ordinary there.

Also, since this began Sab has begun downloading at just 1MBps (that's megaBYTES). I'm on a 100Mb connection and typically see 8-9MBps (megaBYTES) downloads in Sab.

Has anyone seen this before?

[shypike]

I have never seen it saturate my 100 Mbit/sec fiber connection.
Do you have a low speed upload?

Some routers have traffic management and let you designate port 119 traffic as low priority.
(Add 563 for secure Usenet as well).

[TheAmorphous]

~20Mbps up. Wouldn't the router's CPU usage be higher than normal if Sab was saturating a 100Mb connection?

Still no idea what would cause this all of a sudden when I've made no changes.

[shypike]

As an experiment, disable IPv6 support by setting Config->Special->no_ipv6 to "on".

[TheAmorphous]

As an experiment, disable IPv6 support by setting Config->Special->no_ipv6 to "on".

That's actually done it. How strange. Any idea what causes IPv6 to break things that badly?

[shypike]

There were some issues in Beta1.
They will be solved in Beta3, so by that time you could try again.
Then again, if you don't need IPv6, just keep it off.

[TheAmorphous]

Great, thanks for the quick fix. I was afraid my router was crapping out on me for a while there.

[sander]

I would really be surprised if the above is really caused by the bug in 080beta1; that bug can 'only' slow down the setting up of the connections to the newsserver, and only in certain circumstances (if the OS thinks there is IPv6 connection, but there is not). After that, the download speed should be OK. And the bug - AFAIK - can never cause problems for other apps or systems.

So, @TheAmorphous, as soon as Beta3 is out, can you test again, thus setting no_ipv6 to the original value.
You could also test that with 0.7.20 (which hasn't the Beta1 bug), but I'm not sure you're willing&able to do that.

[ALbino]

I have never seen it saturate my 100 Mbit/sec fiber connection.

I'm surprised by that. I saturate my 150mbit fiber connection with SABnzbd every day with no problems.

[TheAmorphous]

It just started doing it again. No IPv6 is still checked. Back to unusably slow.

[TheAmorphous]

I would really be surprised if the above is really caused by the bug in 080beta1; that bug can 'only' slow down the setting up of the connections to the newsserver, and only in certain circumstances (if the OS thinks there is IPv6 connection, but there is not). After that, the download speed should be OK. And the bug - AFAIK - can never cause problems for other apps or systems.

So, @TheAmorphous, as soon as Beta3 is out, can you test again, thus setting no_ipv6 to the original value.
You could also test that with 0.7.20 (which hasn't the Beta1 bug), but I'm not sure you're willing&able to do that.

I would definitely downgrade to 7.2 if I knew how. I'm running Ubuntu and I'm not sure how to go about that and not lose my settings.

As it stands I can't continue using Sab like this. It's wrecking my entire network. What's really odd is that IPv6 change was a magic bullet this morning. Downloads were working fine. Now all of a sudden it's back to being slow.

[sander]

Also, since this began Sab has begun downloading at just 1MBps (that's megaBYTES). I'm on a 100Mb connection and typically see 8-9MBps (megaBYTES) downloads in Sab.

Has anyone seen this before?

Only when using bittorrent (and other high-upload traffic applications) on an asymmetric Internet connection (DSL, cable)

[TheAmorphous]

Also, since this began Sab has begun downloading at just 1MBps (that's megaBYTES). I'm on a 100Mb connection and typically see 8-9MBps (megaBYTES) downloads in Sab.

Has anyone seen this before?

Only when using bittorrent (and other high-upload traffic applications) on an asymmetric Internet connection (DSL, cable)

The connection is literally not being used for anything else right now. When Sab is transferring at 1MBps my throughput on another device on the same LAN drops from 90Mbps to 3 or 4Mbps. Pings increase from 10ms to 400 or even 800+. As soon as I pause the Sab download, everything goes back to normal.

[TheAmorphous]

When Sab is paused, ping from one wired device to another on my LAN averages 2ms. When Sab is downloading it's 600ms. Having IPv6 checked or not doesn't seem to matter now.

Does anyone know what could be causing this?

[sander]

When Sab is paused, ping from one wired device to another on my LAN averages 2ms. When Sab is downloading it's 600ms. Having IPv6 checked or not doesn't seem to matter now.

Does anyone know what could be causing this?

Good test!

My guesses:
- faulty network card / driver causing 'garbage' on your network
- faulty network switch/router
- software like firewall, bittorrent

So, rigorous things you can do to analyze where the problem is:
- instead of a SAB download, do a 1GB download (Ubuntu iso image?) via FTP/HTTP and test the LAN-ping again.
- rule out the current SAB system (turn it off), and let another system do a SAB download, and test the LAN-ping again
- rule out your switch/router, but doing the same basic test on another LAN: take your SAB system + other system to a friend's LAN, and test again