Hello,
On Thu, 2 Aug 2007 19:06:05 +0000 (GMT) John fistack john.fistack@yahoo.fr wrote:
Do you think Dovecot could handle millions of active users in a big architecture ?
Sure, but the architecture will play a bigger role than just Dovecot.
This cluster could be for example (each server is a bi quad Xeon 2.66 Ghz) :
- 40 Dovecot servers
- 4 LVS
- 20 Apache+PHP
- 2 Openldap
- 20 Postfix + ClamAV + SpamAssassin
- 1 NFS Netapps
I'm not sure where you are pulling these numbers from (but then again webmail is a lot more resource intensive than real mail clients). We are handling about 100k users with a total of 9 machines and one SAN backend. And yes, this includes all the components up there with Exim instead of Postfix. About 10-20% are using webmail. 6 machines are cluster pairs, 3 are MXs (no need for clustering there) and yes, any single machine can fail and things will still work, pretty much w/o noticeable performance impact, too. The whole thing is designed to be pretty much indefinitely scalable.
For historical reasons we stayed clear of NFS (this system architecture has been in production for 7 years, the last 3 with Dovecot), so I can not comment on that part from own experience. But I have a hard time imagining any single storage backend not melting from the traffic that these amounts of machines would generate (if they are actually needed). And even if the backend could handle it, the network towards it would be saturated a long time before those 40 Dovecot servers would run out of steam CPU wise.
Regards,
Christian
Christian Balzer Network/Systems Engineer NOC chibi@gol.com Global OnLine Japan/Fusion Network Services http://www.gol.com/