[Dovecot] Performance based choices

[Robert Schetterer]

Am 22.07.2012 15:39, schrieb Hans J. Albertsson:
> I've stopped trying to find a HowTo that suits me right away, and
> instead I am happily trudging thru the Dovecot wiki, article by article.
> 
> I have right up front thought of one question, a general one, and some
> detailed versions of that same question:
> 
> Generally, is there much general performance and reliability background
> data available for making the basic choices?
> 
> Say: 1st.
> delivery:
> maildrop or LDA or LMTP?

lmtp should be fine

> I tend to think LMTP should be the ideal choice for me, from what I've
> gleaned so far.
> Above all it means that there's only one conceptual thing that needs to
> know, and postfix and other stuff can safely let dovecot deal with
> accessing and finding mailboxes.
> And it won't start and stop thousands of processes.
> 
> 2nd.
> mailbox format: Maildir and mbox are the older forms. Are there any
> advantages to using dovecot's dbox instead? mdbox strikes me as having
> the potential for being a fast and reliable format. Is that an accurate
> impression? And, is mdbox mature enough for me to forget maildir and mbox?

mdbox maybe the best choice

> 
> 3rd.
> I'm aiming for a poor man's High Availability system:
> I'm using zfs, and I'm hoping to place all config data for dovecot and
> postfix and everything else in one zfs file system, and all the user
> owned data (what should normally go in a home directory) in another (or
> two or three other) zfs file systems.
> Then I'm planning to copy over all data at regular intervals, to a
> second, normally passive, mail server. If the main server breaks, we'll
> manually (or using scripts and autodetection) fail over to the passive
> one, making it active, and turning power off to the failed guy using IPMI.
> The data transfer is to be zfs send/zfs recv over a separate highly
> redundant network connection.

for poor man
i would recommend master/master drbd and some cluster filesystem i.e
ocfs2 etc, for backup you may use dsync

with loadbalancing i.e keepalived etc
anyway you need a "quick" storage for imap

a standby soltution maybe good too, but why not simply use loadbalancing

> Is this a reasonable idea, or is there some advantage to letting dsync
> do some of the copying??? Or is there some totally different
> alternative? iscsi?
> 
> 4th.
> With about a thousand users/accounts: does MySQL pay off? Or is LDAP the
> way to go? Or will a dovecot-specific passwd-file do the job well enough?
> Those are the three I'm used to since before.
> I'd like to stay with the flat file, but not the system password file:
> we're not going to let users in except into dovecot.

with modern hardware/kernel  cpu and mem thousends of user accounts are
no problem with mysql, but i guess same is in ldap

anyway this is only my meaning, wait till you heard more ones before act

Perhaps you should give more additional info like planned standard quota
of mailboxes
awaited average user cons etc
for better advice



-- 
Best Regards
MfG Robert Schetterer