Bruce Guenter wrote:
>
>
> As promised, I've posted the results of the benchmark testing at
> http://em.ca/~bruceg/bench-qmail-remote/
>
> The receiving server is my PC, which has a DSL connection running at
> about 1.5Mb downlink bandwidth (the part that was actually used) running
> qmail, of course. The "-cable-" results were sent from a cable modem
> which has approximately 384Kb uplink bandwidth. the "-2Mb-" results
> were sent from a partial DS3 with 2Mb of bandwidth. The receiver had
> its concurrency set to 128.
>
> 20 runs were done of each test, 10 with one connection with multiple
> recipients, and 10 with multiple connections with one recipient. The
> min and max columns give the fastest and shortest run times
> respectively; mean is (T1*T2*T3...*T10)**(1/10); avg is
> (T1+T2+T3+...+T10)/10. The mean is less biased by unrepresentative
> results, and so is a better measure of the common case.
>
> Conclusions are somewhat tricky. Using mutiple RCPTs tends to be more
> predictable (less of a spread between min and max), but using multiple
> connections has the best optimistic behaviour (min is lower than
> multi-RCPT's min). With small messages (4KB and less), multi-connection
> is always a win. On our mail proxy, the median message size is 3KB,
> just for comparison. On the well-connected sender, using multi-RCPTs
> was never a significant win, which proves DJB's hypothesis about its use
> for well-connected hosts. Once bandwidth limits become an issue (poorly
> connected server, large messages), multi-RCPTs win because the latency
> involved in sending one more RCPT becomes less than the additional time
> required to send another concurrent copy.
>
> This says nothing about bandwidth efficiency, only time efficiency.
> Obviously, using multi-RCPTs is always a bandwidth win (unless your
> recipient is larger than your message, highly unlikely).
>
> Feedback would be appreciated. Oh, and please don't consider the test
> addresses I used in the scripts as wide open for mailbombing.
Thanks for that - very interesting.
Here goes on some feed back ...
Very interesting - you seem to have backed up DJb's claims that a well
connected host using single RCPTS is probably as good as one using
multiple RCPTs. I always thought that Multiple would win hands down....
One of my clients is into sending "customized - personal" messages to
their members - and we've been looking at an mta solution.
We are using sendmail - I'm a big qmail fan, use it it lots of places,
but have been reluctant to change a working system. One of the
arguments against was the multiple rcpt-to's that qmail does not
support.
My question is thus - When does a host become well connected ?
The reason being is that we use two hosts - one is a SuSe based Linux
box (256 meg RAM - 1 9 GIG scsi, and a pentium 600) the a twin
ultrasparc 1 gig ram - 1 9 gig scsi that is also our main web server /
mysql server.
The Suse box is at an ISP without good bandwidth, the Sun box is in one
of the best connected places in the UK (were "well connected" is usually
an order of magnitude below the US ). I would define well connected at
anything above 512 mbits/sec.
Thanks again.
Greg Cope
still awaiting ADSL to be launched in the UK!
> --
> Bruce Guenter <[EMAIL PROTECTED]> http://em.ca/~bruceg/
>
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