Large imap server.

[Francisco Reyes]

Bill Campbell writes:

> Cyrus scaling?


We currently user Courier and so far I am far from impressed with it's 
scalability.

We have NFS servers for the storage and then front end machines for the 
POP/IMAP connections. The footprint per connection is about 3MB to 5MB on 
the client. On a machine with 2GB that means about 600 connections... but 
the machines usually are dying around 400 connections.


> Perhaps on one mongo server. 

I have read totally the opposity that the only way to scale a mail setup 
beyond 10s of thousands is with Cyrus .. or some other propietary system. 
Have note read of any truly large Courier installation.

> imap from a central server housing home directories, and have
> seen essentially linear performance as servers are added.

How many connections can you handle per "front-end" machine?
What type of configuration? I inheritted the setup I am working with and 
little by little we are building things "right".. including better mail 
store machines.

Also as part of the initial question was which sysctl/kernel settings are 
usefull in dedicated mail clients/servers