On Wed, Nov 01, 2000 at 12:53:27PM +0000, Greg Cope wrote:
>Out of interest does the Netfilter have a large / battery backed cache
>to decrease the I/O / disk bottle neck ?
Yes. They have a chunk of NVRAM which ACKs the write request as soon as it's
committed there. This gives it the ability to ack write messages very quickly
while still ensuring that the data is resiliant to crashes.
>Also does your system only send one message - the ones I deal with are
>all individual (both in content and message headers).
That's the problem. It's relatively slow throwing a bunch of messages
into QMail. It doesn't take a very powerful machine to completely swamp
a fairly hefty QMail server, I've found. And since the smtp daemons
are fat, dumb, and happy individual processes, they don't really have the
smarts to do any sort of throttling on incoming connections.
We ended up having to implement that sort of thing externally so that the
originating program wouldn't swamp the box.
>> Short of a threaded qmail-remote (or qmail-send/qmail-remote hybrid), a
>> pre-forked pool of qmail-remotes waiting on a common socket would probably be
>> a significant improvement. In short, Apache-style process management.
Well, remember that Apache is pre-forking the *LISTENERS*, not originators.
So the exact setup wouldn't exactly be relavent. What you really want to
be able to do is keep an existing session open to a mail server and shove
additional messages down it.
I realize that DJB has numbers which say it's faster to open 10 independant
connections than to stream 10 messages over 1 connection. If you're
already at concurrencyremote I suspect it's just a waste of time to
shut down a connection when you're just going to open it again.
Also, pre-forking is only really relavent when you have *ANTICIPATED*
load. If you actually have more messages to deliver, it's not called
pre-forking. ;-)
Sean
--
Laws are the source code to our government. Submit a patch November 7.
VOTE! November 7, 2000
Sean Reifschneider, Inimitably Superfluous <[EMAIL PROTECTED]>
tummy.com - Linux Consulting since 1995. Qmail, KRUD, Firewalls, Python
