...snip... If you can direct all your mail client accesses through IMAP or POP, leaving no programs but the delivery agent and the imap/pop daemon doing direct mailbox accesses, then you get the ability to relatively painlessly change mailbox formats. That's worthwhile; Maildir+NetApp is one of the sweetest spots in the whole mail server design spectrum. Forget locking, forget recovery, everything Just Works.
When I build a server, even if it's a single box for everything, I go with maildrop delivering to virtual user Maildirs, with Courier-IMAP (which offers pop, and the /ssl varients) providing access for MUAs; this sets me up to grow as big as ever I could want and never worry about mailbox correctness.
I'd like to echo those sentiments: I build mail systems - the Maildir / NetApp combo means that my largest client currently has a system with 1.6 million Maildirs ( = users) and it's still growing nicely. I wrote to highlight qmail - "The original and best" mailserver to use Maildirs. Qmail is a particularly strong mailserver implementation and is very stable - I have some concerns with Courier mentioned by Bennett in that a new version seems to appear frequently.
The other nice thing about Maildirs is that because of their (as Bennett says) "everything Just Works" design, you can have multiple machines writing entries (messages) to the same Maildir without their needing to be aware of one another's existence; that really helps systems to scale.
More info on qmail at www.qmail.org and cr.yp.to/qmail.html
cheers,
Andrew.
2002-10-01-04:16:25 Andrew Richards:
I wrote to highlight qmail - "The original and best" mailserver to use Maildirs. Qmail is a particularly strong mailserver implementation and is very stable - I have some concerns with Courier mentioned by Bennett in that a new version seems to appear frequently.
I followup only to mention that my choice of Courier applies only to the IMAP (and POP) daemons (the Courier-IMAP package), and the maildrop Local Delivery Agent, which work together to support a very nice virtual user architecture around /etc/userdb.
For MTA, qmail is definitely one of my top two choices. I personally prefer to use Postfix, but when making recommendations to others I try to just advise them to use one or the other of those two, whichever they like best.
This is wandering off-topic for the toasters list, I'm afraid; if anyone wants to discuss MTA choices more, do please feel free to drop me a note off-list. What can be said here with relevance is that there are some of us who adore using NetApps as the heart of big mail farms with Maildirs as the enabling data structure. If I'm remembering aright, there was a tasty paper a few years back about some large ISP (Earthlink, maybe?) who took this approach and came away happy.
-Bennett
On Tue, 2002-10-01 at 14:09, Bennett Todd wrote:
This is wandering off-topic for the toasters list, I'm afraid; if anyone wants to discuss MTA choices more, do please feel free to drop me a note off-list. What can be said here with relevance is that there are some of us who adore using NetApps as the heart of big mail farms with Maildirs as the enabling data structure. If I'm remembering aright, there was a tasty paper a few years back about some large ISP (Earthlink, maybe?) who took this approach and came away happy.
We're currently using an F760 mounted onto 20 servers for our mail system. We use Courier (POP3) for the 10 reader boxes, and Exim4 for the 10 MTA boxes, obviously using maildir over NFS.
This setup is merrily handling around 5 million inbound emails a week. We're very happy with maildirs on a netapp.
Jerry.
On Tue, Oct 01, 2002 at 09:16:25AM +0100, Andrew Richards wrote:
The other nice thing about Maildirs is that because of their (as Bennett says) "everything Just Works" design, you can have multiple machines writing entries (messages) to the same Maildir without their needing to be aware of one another's existence; that really helps systems to scale.
Maildirs work very well.
More info on qmail at www.qmail.org and cr.yp.to/qmail.html
Or if you want something that is easy to configure and has a continuing history of development without the 'linux new version of the day', check out Postfix (http://www.postfix.org/) which supports Maildir format out of the box as well as mbox format allowing you to 'change' from one to the other when you are ready.
-
Andrew Richards -
Bennett Todd -
Jerry Nicholls -
Mike Horwath