Cyrus vs Dovecot

Pascal Gienger Pascal.Gienger at
Tue Aug 12 11:51:46 EDT 2008

Adam Tauno Williams <adam at> wrote:

> If you have allot of users and allot of mail you are going to have allot
> of I/O.  No way around that, regardless of the server.  Cyrus' indexes
> headers better now, so that might help.  But you still need adequate
> through-put.  I've found that /var/lib/imap (meta-data) needs fast I/O
> but /var/spool/imap (message store) doesn't due too bad tossed onto a
> SAN or slower disks.

That depends how many mails per second you will have to deliver.
Normally you are right, the meta partition is heavy random i/o.
With high mail receiving rates you need a fast write storage for your imap 
spool as well. Filesystems like ZFS which write their contents nearly 
sequentially are ideal for this kind of work.

And: Use a 64bit system and add much RAM. Your OS will (hopefully) cache 
all metadata which is heavily used in RAM. We are having 98% hits on our 
meta partition.

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