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2117e02e MW |
1 | qmail's modular, lightweight design and sensible queue management make |
2 | it the fastest available message transfer agent. Here's how it stacks up | |
3 | against the competition in five different speed measurements. | |
4 | ||
5 | * Scheduling: I sent a message to 8192 ``trash'' recipients on my home | |
6 | machine. All the deliveries were done in a mere 78 seconds---a rate of | |
212b6f5d | 7 | over 9 million deliveries a day! Compare this to the speed advertised |
2117e02e MW |
8 | for Zmailer's scheduling: 1.1 million deliveries a day on a |
9 | SparcStation-10/50. (My home machine is a 16MB Pentium-100 under BSD/OS, | |
10 | with the default qmail configuration. qmail's logs were piped through | |
11 | accustamp and written to disk as usual.) | |
12 | ||
13 | * Local mailing lists: When qmail is delivering a message to a mailbox, | |
14 | it physically writes the message to disk before it announces success--- | |
15 | that way, mail doesn't get lost if the power goes out. I tried sending a | |
16 | message to 1024 local mailboxes on the same disk on my home machine; all | |
212b6f5d | 17 | the deliveries were done in 25.5 seconds. That's more than 3.4 million |
2117e02e MW |
18 | deliveries a day! Sending 1024 copies to a _single_ mailbox was just as |
19 | fast. Compare these figures to Zmailer's advertised rate for throwing | |
20 | recipients away without even delivering the message---only 0.48 million | |
21 | per day on the SparcStation. | |
22 | ||
23 | * Mailing lists with remote recipients: qmail uses the same delivery | |
24 | strategy that makes LSOFT's LSMTP so fast for outgoing mailing lists--- | |
25 | you choose how many parallel SMTP connections you want to run, and qmail | |
26 | runs exactly that many. Of course, performance varies depending on how | |
27 | far away your recipients are. The advantage of qmail over other packages | |
28 | is its smallness: for example, one Linux user is running 60 simultaneous | |
29 | connections, without swapping, on a machine with just 16MB of memory! | |
30 | ||
31 | * Separate local messages: What LSOFT doesn't tell you about LSMTP is | |
32 | how many _separate_ messages it can handle in a day. Does it get bogged | |
33 | down as the queue fills up? On my home machine, I disabled qmail's | |
34 | deliveries and then sent 5000 separate messages to one recipient. The | |
35 | messages were all safely written to the queue disk in 23 minutes, with | |
36 | no slowdown as the queue filled up. After I reenabled deliveries, all | |
37 | the messages were delivered to the recipient's mailbox in under 12 | |
38 | minutes. End-to-end rate: more than 200000 individual messages a day! | |
39 | ||
40 | * Overall performance: What really matters is how well qmail performs | |
41 | with your mail load. Red Hat Software found one day that their mail hub, | |
42 | a 48MB Pentium running sendmail 8.7, was running out of steam at 70000 | |
43 | messages a day. They shifted the load to qmail---on a _smaller_ machine, | |
44 | a 16MB 486/66---and now they're doing fine. |