[nzlug] Slow uploads to Trademe

[cr]

On Tue, 08 Aug 2006 07:42, Mark Foster wrote:
> On Tue, 8 Aug 2006, cr wrote:
> > Just an update - problem solved.   I couldn't find anything in my system
> > log files so I asked on the Debian-user list and got a reply 'Maybe MTU
> > problem?'  (which is about as cryptic as one could get).
> > So after I found out what a MTU is   8)    and fiddled with the line 'mtu
> > <n>' in my /etc/ppp/options  it now all works perfectly!!!
> > (mtu 1024 improved things but not complete cure,  mtu 512 is the answer
> > in my case).
> >
> > (..."Maximum Transmission Unit" -  roughly = 'packet size')
> >
> > cr
>
> You should be aware having set an MTU other than the ethernet default
> (~1500) is going to result in vastly decreased performance across the
> board.
>
> When you deal with large files you're going to find that they are going to
> be forced to fragment to get past your MTU restriction, which in turn is
> going to be reducing throughput and increasing load.
>
> If you need to limit yourself to a 512 byte MTU to deal with Trademe, i'm
> a little concerned...
>
> Mark.

Well yes, that occurred to me too.   However, I just UL'd a 160K  JPEG to 
Trademe with that setting and it went as fast as I've ever managed to do any 
upload anywhere.   (This of course may not say much for the usual state of my 
setup   ;-)

However my old Woody system still uploads OK without me manually setting any 
MTU at all (I presume PPP uses some default).   So does (shudder!) W98.

However, having totally failed to find any other cure for the problem, or even 
where it might be, this ad hoc measure works so I'll use it till I can find a 
better.   I haven't tried checking the PPP documentation but I think I could 
probably set MTU for one of my ISP's (say Orcon) and do all my uploads to 
Trademe via them, and leave my other ISP (Clear) unset and do uploads to all 
else via them.   (Why have I got two ISP's? - historical reasons.   It might 
change if broadband gets truly cheap).

I'm far from an expert on PPP (!); if anyone can suggest any other lines of 
investigation I'll give them a try.   Trademe could only suggest I try using 
a Windows PC - I suggested they try saying that to a Mac user  <g>

cr