qmail's modular, lightweight design and sensible queue management makeit the fastest available message transfer agent. Here's how it stacks upagainst the competition in five different speed measurements.* Scheduling: I sent a message to 8192 ``trash'' recipients on my homemachine. All the deliveries were done in a mere 78 seconds---a rate ofover 9 million deliveries a day! Compare this to the speed advertisedfor Zmailer's scheduling: 1.1 million deliveries a day on aSparcStation-10/50. (My home machine is a 16MB Pentium-100 under BSD/OS,with the default qmail configuration. qmail's logs were piped throughaccustamp and written to disk as usual.)* Local mailing lists: When qmail is delivering a message to a mailbox,it physically writes the message to disk before it announces success---that way, mail doesn't get lost if the power goes out. I tried sending amessage to 1024 local mailboxes on the same disk on my home machine; allthe deliveries were done in 25.5 seconds. That's more than 3.4 milliondeliveries a day! Sending 1024 copies to a _single_ mailbox was just asfast. Compare these figures to Zmailer's advertised rate for throwingrecipients away without even delivering the message---only 0.48 millionper day on the SparcStation.* Mailing lists with remote recipients: qmail uses the same deliverystrategy that makes LSOFT's LSMTP so fast for outgoing mailing lists---you choose how many parallel SMTP connections you want to run, and qmailruns exactly that many. Of course, performance varies depending on howfar away your recipients are. The advantage of qmail over other packagesis its smallness: for example, one Linux user is running 60 simultaneousconnections, without swapping, on a machine with just 16MB of memory!* Separate local messages: What LSOFT doesn't tell you about LSMTP ishow many _separate_ messages it can handle in a day. Does it get boggeddown as the queue fills up? On my home machine, I disabled qmail'sdeliveries and then sent 5000 separate messages to one recipient. Themessages were all safely written to the queue disk in 23 minutes, withno slowdown as the queue filled up. After I reenabled deliveries, allthe messages were delivered to the recipient's mailbox in under 12minutes. End-to-end rate: more than 200000 individual messages a day!* Overall performance: What really matters is how well qmail performswith your mail load. Red Hat Software found one day that their mail hub,a 48MB Pentium running sendmail 8.7, was running out of steam at 70000messages a day. They shifted the load to qmail---on a _smaller_ machine,a 16MB 486/66---and now they're doing fine.