Cyrus vs Dovecot
Pascal Gienger
Pascal.Gienger at uni-konstanz.de
Tue Aug 12 11:51:46 EDT 2008
Adam Tauno Williams <adam at morrison-ind.com> 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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