Not to draw this thread out anymore, but I moved away from qmail for a number of reasons. I ran a big mail cluster with it, handling about 4 to 5 million messages a day, sometimes double that. Qmail is a pain in the ass to maintain, and many options come in patches not with the program itself. You need to run it under daemontools, which sometimes gets confused and tries to start it when it's already running. It won't start a second copy, but it will fill your logs with error messages. When the queue gets above 27,000 messages, it gets *really* slow. I applied the big-todo patch, but it still wouldn't handle more than about 45,000 messages. You have to be careful with the big-todo patch because if you choose a prime that is very large, you end up with such a big directory structure that it really hurts your performance. I spent a lot of time tweaking qmail, and an obscene amount of time administering the cluster. Oh, and the logs qmail generates are garbage. Getting stats from them or searching for a message is like trying to squeeze blood from a rock. You need to find the line with the address you are looking for, and then take the message id and grep for that to find all related lines. When the log file is very large, the id's wrap, and you get lines from other messages. I switched to postfix, because in my tests I was able to get much higher performance out of it. Configuration changes can be done with the "postconf" command rather than editing a config file. This makes it great for a cluster setup because you can have a script that will execute your config changes across the cluster without having to go to every machine. Large queues are no problem for postfix, and it doesn't seem to be bound by the FD_SET limit in the kernel (which is not easily modified in linux). With qmail, under linux, you can have at max 509 qmail-smtp delivery processes going at once, this is because qmail-smtp is a child process of qmail-rspawn. qmail-rspawn holds onto the file decriptors for each message. It opens 2 descriptors for each message, and at 509 outgoing processes, you have 1018 file descriptors open, plus whatever else qmail-rspawn is holding onto just to run. Once you go above 1024, qmail will crash. This is not modifiable in /proc or with ulimit. This is compiled into the kernel and is a hard limit on how many file descriptors each process can have open at any one time. It's not a simple setting to just change and recompile. There was a patch for older 2.2 kernels to change this, but there is no patch I know of for the 2.4 kernels. Postfix isn't as greedy with file descriptors as qmail is, but you will eventually run into limits. I've moved to freebsd where you can change the limits at compile time using the -DFD_SETSIZE= option. Postfix runs great, even when there are 2048 delivery processes currently active. Also, qmail hits the disk roughly 3 times more than postfix does. Under heavy volume, most of your bottleneck is going to be disk IO, so if you have slow disk, or are doing REALLY high volume, Postfix is definitely going to help you. Jay > -----Original Message----- > From: David Dyer-Bennet [mailto:dd-b at dd-b.net] > Sent: Wednesday, July 24, 2002 10:06 PM > To: tclug-list at mn-linux.org > Subject: Re: [TCLUG] how about QMail? > > > "Chad C. Walstrom" <chewie at wookimus.net> writes: > > > On Wed, Jul 24, 2002 at 11:08:50AM -0500, anID10T wrote: > > > any thoughts about Qmail? or better, Qmail and Red Hat 7.x ? > > > > DJB sucks! OK, not really. The author of Qmail had a set of goals > > that he feels he's met. As a CS professor, he knows what > he's doing, > > and for many people, qmail is a great server. It's the > licensing of > > qmail that makes many Free Software advocates jumpy. > Frankly, DJB's > > software is not Free, as in "free beer". This does not make it bad > > software, just not a favorite amongst those who are > "license jumpy". > > I would include myself in those numbers. I'd rather avoid > licensing > > issues, and therefore choose MTA software like postfix, exim, or > > sendmail. > > Dan Bernstein is is of course an UberGeek, with all the > rights and priveleges appertaining thereto :-). Luckily, he > rarely has anything to do with the qmail mailing list, and > the crew that *does* hang out there is extremely knowledgable > and helpful. > > Meanwhile, qmail is small, fast, and secure. Compare sizes, > in particular, the alternatives Chad offers. Even assuming > that Wietse, say, wrote as good code as Dan did (seems a > reasonable assumption), the smaller quantity and the clean > functional partitioning should give > -- > David Dyer-Bennet, dd-b at dd-b.net / New TMDA anti-spam in > test John Dyer-Bennet 1915-2002 Memorial Site > http://john.dyer-bennet.net > Book log: > http://www.dd-b.net/dd-b/Ouroboros/booknotes/ > New Dragaera mailing lists, see http://dragaera.info > _______________________________________________ > Twin Cities Linux Users Group Mailing List - Minneapolis/St. > Paul, Minnesota http://www.mn-linux.org > tclug-list at mn-linux.org > https://mailman.mn-> linux.org/mailman/listinfo/tclug-list >