Re: slow delivery for big messages?

[Matti Aarnio <mea@nic.funet.fi>]

On Thu, Aug 19, 2004 at 04:46:39PM -0400, Stuart Chase wrote:
> Any help is appreciated.
> 
> I have zmailer 2.99.54 running on Redhat AS2.1 for five months 
> and until a couple of days ago, all was fine. No changes have been 
> made to the system.
> 
> From this zmailer to one novell server, and only this one novell 
> box, it is extremely slow delivering emails. This is especially 
> noticeable when the emails have attachments >1 meg. 
> In fact you can do a ps -ax |grep servername and watch the 
> delivery process as it slowly moves the data across, 9%, a couple 
> of minute later issue the same command and it is at 12% - this is 
> on a 1.3Meg email!
> All other connections to and from this zmailer server, including big 
> attachments, are fine. The same is true for the novell box.

I recall having seen some similar problem once with SPARC Solaris 2.6
being sending machine, and receiver being some windows machine.
Running tcpdump (or 'snoop' as solaris has) at ZMailer side did show
very bad network performance in between the two machines.  Lots of
transmission retries etc.  At the same time then current Linux (2.2
or 2.4, I don't remember anymore) talked with the same windows box
just fine...

> There is a way I can send the same large attachment to the zmailer 
> server in question, which goes to another zmailer server (which has 
> spam assasin and mailscanner), this other zmailer server delivers 
> fine to that novell server. It seems that the problem is only with 
> these two systems. They are on the same network, no routers 
> between nor any rate limiting going on.
> 
> On the zmailer server, anywhere there is a server specific entry, 
> the syntax for the entries are identical for problem and good 
> servers. 

The ZMailer's perhaps are identical, but what about the operating
systems underneath each box ?   Are they the same ?  With same
network feature setup ?   'uname -a' will tell you operating system
version, a "Redhat AS2.1" in itself doesn't say much.

> Anyone have a suggestion how to speed up or at least figure out 
> why it is taking so long?
> 
> Thanks!
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> Stuart Chase
> Co-ordinator Telecommunication Services, Postmaster
> Dept. of Information Technology and Services
> Mount Saint Vincent University
> Halifax, Nova Scotia, Canada
> Phone - 902-457-6292
> Stuart.Chase@MSVU.Ca
> http://www.msvu.ca

-- 
/Matti Aarnio	<mea@nic.funet.fi>
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