[Dovecot] Question about "slow" storage but fast cpus, plenty of ram and dovecot

[Kerem Erciyes]

Hi,

I am running a fair amount of stored e-mails on maildirs(10 GB+) in 846
folders that gets a fair amount of searching, and 20+ users accessing them,
mostly via IMAP and a few POP3 accounts. I am running these on a Linode XEN
server and have yet to hit any hard limits of "bare metal". User and Virual
databases are plain text files.

# 1.2.9: /etc/dovecot/dovecot.conf
# OS: Linux 2.6.32.16-linode28 i686 Ubuntu 10.04.1 LTS ext3

Postfix + Dovecot + SSL for Both with Amavisd seems a breeze. No problems
related to infrastructure yet.

Yet I will wait to see how this system will grow, as we are planning to
include more users and doamins in our system in 2011.

So:

1. I am very interested in these questions about performance
2. My setup should provide some people another way to do things, since I am
not using mysql, ldap etc., kust plain old text files update via scripts
3. I am goind to test this system as we scale out, yet we are bound to add
LDAP for authentication for single sign on at some point, and I will try to
publish my benchmarks public, even if it is just for publicity's sake.

Regards,
Kerem


On Sat, Dec 11, 2010 at 6:47 PM, Eric Rostetter
<rostetter at mail.utexas.edu>wrote:

> Quoting a at test123.ru:
>
>  Guys. Who is interested in obvious reasoning?
>>
>
> The same people who are interested in vague questions?
>
>
>  Let me remind original concrete question. I am also interested.
>>
>>  We can "exchange" CPU & RAM to minimize disk i/o.
>>> Should we change to dovecot 2.0?
>>> Maybe mdbox can help us?
>>> Maybe ext4 instead of ext3?
>>>
>>
> Uhm, well, again, depends on your needs.  Pop3? Imap? Both?  Number of
> accounts?  Can't really help without more details.  Maybe I can't help
> with more details either, but that is a risk you take on a mailing list.
>
>
>  1. Is migration to dovecot 2.0 good idea if I want to decrease I/O?
>>
>
> Depends on what version you run now really.  But I would recommend it
> anyway just on principle.
>
>
>  2. Can mdbox help decrease IO?
>> 3. What is better for mdbox or maildir - ext3 or ext4?
>>
>
> Dont' know.  But you can certainly tune the FS in either case (atime/dtime,
> flush rate, external journal, etc).  Some will say XFS is better, etc.
> Besides, you can hardly decide the best FS until you know the mailbox
> format (mbox, maildir, mdbox, etc).
>
> If you want concret answers, you need concret questions...
>
>
> --
> Eric Rostetter
> The Department of Physics
> The University of Texas at Austin
>
> Go Longhorns!
>
>


-- 
Kerem Erciyes
Sistem Danismani
http://proje.keremerciyes.com

kerem.erciyes at gmail.com
+90 532 737 05 83