[Bio-Linux] Bandwidth cont.

[Alec Colebrook-Clark]

Hi Tim and Tony,

> As Tony says, we need you to be a bit more specific about what you are doing on Bio-Linux that "hammers" the WAN.  

All I am doing in this particular instance is downloading a collection of large files using 'wget' once I have ssh'd into the machine. I need to experiment more with the limit to see if it has the desired effect but initial tests aren’t looking great. I will have to try this more next week. It is worth noting that any package updates don’t cause an issue but I believe that is to do with their relatively small size.

> It's common to rate-limit APT package updates because this is considered a low-priority operation, but if just downloading a file in Firefox, say, is >snagging up the network then this would seem to be a more serious issue and possibly a network issue.  In normal operation Linux is very well >behaved in accessing the network - for example I run package updates at home over the broadband router and other devices can still access the >internet.

I haven’t tried to see if the issue happens through a GUI. I normally just ssh in and run the download with 'wget'. We have other linux (virtual) machines and they are very well behaved. I shall discuss with the network manager to see if he can think of anything that might cause this.

> However, The way that "wget" and "sftp" limit bandwidth is by sleeping between blocks as the transfer proceeds. You're right that it won't make >much difference on a system that is not limited by CPU resources.

The machine isn’t limited on CPU but I shall look into it nonetheless. 

Thanks both for the advice, I have some further ideas now to try and tackle this problem!
Alec 

-----Original Message-----
From: bio-linux-bounces at nebclists.nerc.ac.uk [mailto:bio-linux-bounces at nebclists.nerc.ac.uk] On Behalf Of Tim Booth
Sent: 12 July 2013 14:09
To: bio-linux at nebclists.nerc.ac.uk
Subject: Re: [Bio-Linux] Bandwidth cont.

Hi Alec,
 
As Tony says, we need you to be a bit more specific about what you are doing on Bio-Linux that "hammers" the WAN.  Downloading a large file on Bio-Linux should be no different to downloading a large file to any Windows machine, which I'm sure you do all the time, and I'd expect the network architecture to share bandwidth fairly without snarling up.

It's common to rate-limit APT package updates because this is considered a low-priority operation, but if just downloading a file in Firefox, say, is snagging up the network then this would seem to be a more serious issue and possibly a network issue.  In normal operation Linux is very well behaved in accessing the network - for example I run package updates at home over the broadband router and other devices can still access the internet.

Cheers,

TIM
> 
> @TIM – the problem is a single box hammering the WAN. I tried to 
> throttle the machine but it only effected the its LAN capabilities and 
> not the download (which is happening over the same connection). Is 
> there any way I can trace what is happening?
> 
>  
> 
> Thanks for the help
> 
> Alec
> 
>  
> 
> 

--
Tim Booth <tbooth at ceh.ac.uk>
NERC Environmental Bioinformatics Centre 

Centre for Ecology and Hydrology
Maclean Bldg, Benson Lane
Crowmarsh Gifford
Wallingford, England
OX10 8BB 

http://nebc.nerc.ac.uk
+44 1491 69 2705
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