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Date: Wed, 24 Sep 2008 00:04:25 +0200 (CEST)
From: Wojciech Puchar <wojtek@wojtek.tensor.gdynia.pl>
To: Laszlo Nagy <gandalf@shopzeus.com>
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Cc: freebsd-questions@freebsd.org, Tony Nagy - SHOPZEUS <tony@shopzeus.com>
Subject: Re: dovecot, maildir, UFS 2 performance
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> dir goes to SATA.
>
> The secondary task for this server is to be an IMAP and mail server. We will 
> be using dovecot, and shared maildir folders with ten thousands of messages. 
> I'm not sure where to put the maildir folders, and what options to use for

unless you have tens of thousands of mail users, put it anywhere ;) it 
will work fine.

> #1 maildir stores each message in a separate file. I think I need to dedicate 
> a separate disk slice for maildirs and decrease block size on it. How big 
> should the blocksize be?

i have everything (/) on single partition on most of my servers, including 
those having lots of mail.

i too use dovecot and maildirs.

default fragment size of 2K is fine, average mailfile size is not that 
small to bother making smaller fragments.


> #2 searching in messages is a common operation. Possibly read speed is very 
> most important. But since there will be thousands of files to open, seek 
> operation is also important. On which RAID array should I put mail dirs?

dovecot do make indexes and scans all files only when rebuilding them.

> Small SAS or bigger SATA array?

assuming you configured your RAID1+0 properly it will give you MUCH more 
performance from 10 disks, than RAID1 on 2 - a bit faster - drives.

IMHO you wasted money for SAS drives, simply having SATA only system could 
be enough.


just keep your SAS drives for OS, ports, sources, logs, whatever, while 
/home on your big RAID1+0 volume.