[CentOS] Large scale Postfix/Cyrus email system for 100,000+ users

Thu Oct 25 04:55:29 UTC 2007
Christopher Chan <christopher at ias.com.hk>

>> Yeah, well, I guess the Fedora Directory server is unlikely to drop 
>> its entire datastore and will actually keep running but hey, are you 
>> going to migrate back to ldap if you have a system that is distributed 
>> across different mysql boxes running on cheap boxes and does its job?
> Yes, I've had enough trouble with mysql that I'd look for any 
> alternative, but to be far that was a few years back too.

A few years back was when I worked with mysql in a multi million mailbox 
environment with dual PIII mysql servers. Once I stuffed the customized 
sendmail in the bin and replaced it with postfix and its connection 
caching capabilities, those mysql boxes became the most stable part of 
the system. See my post to Craig. These are versions 3.xx and 4.0.x

>>> But the openldap guys think they are better - see page 33 of the pdf 
>>> linked from this page: 
>>> http://www.mail-archive.com/ldap@umich.edu/msg01151.html
>>> (22000 queries/sec, 4800 updates/sec on a terabyte database with 150 
>>> million entries - but I think the test box had 480Gigs of RAM...)
>> There you go. If you have the hardware, you can do openldap. 480Gigs? 
>> Did you add an extra zero?
> I copied it from this email post.
> http://www.redhat.com/archives/fedora-directory-users/2007-July/msg00113.html 

Well, that is some serious hardware. My experience was with dual PIII 
and later P4 based Xeons...

>>>>> Does anyone have enough faith in a free NFS server to use it in 
>>>>> this scenaro these days?   How about opensolaris on top of zfs?
>>>> I would say. No comment on opensolaris in this scenario but I am 
>>>> happy with zfs as an offsite online backup solution.
>>> Are you using the incremental send/receive operation for this?
>> Huh? This is just rsync for the vpopmail maildir, user home 
>> directories, pervasive database files and scp for an Exchange backup 
>> file and then snapshotting on the zfs volume for the vpopmail and user 
>> home directories. Nothing heavy. What is this incremental send/receive 
>> operation that you are talking about?
> zfs has the ability to make filesystem snapshots, then back them up with 
> a send/receive operation.  See bottom of this page 
> http://docs.sun.com/app/docs/doc/819-5461/ftyxi?a=view.  I haven't used 
> it myself but it sounds handy.

Single OpenSolaris box. I don't have an exciting environment anymore :-(