Qmail Support Forum

admin · Site Admin Joined: 21 Jun 2005 Posts: 210

Hi all,

I have to plan and setup a mail solution for about 50.000 users, here are
some key features requested by our customer:

- self coded webfrontend w/ webmail and administration (filter, alias etc)
- 100MB quota per user
- autoresponder
- about 50.000 user
- online backup of data
- some more featuers for web frontend

Since I happily use qmail for some other (but smaller) installations, I
want to try it with qmail here for this project as well. My only problem
is, I have no clue where to start ... beginning from "should I use 2
redundant and really strong or some more but cheaper servers?" to "which
qmail distributions and patches should I use (ldap, mysql, ...)?" and "how
to store data (mails) and do online backup w/o downtime?".

I know you can't give me _the_ solution for this issue, but I am thankful
for any hints and internet links on this topic.

I am sure you guys can help me Smile

Greetings and TIA, Matthias

admin · Site Admin Joined: 21 Jun 2005 Posts: 210

I'm not sure what you mean by self coded. Squirrelmail is a webmail front
end that meets the requirements you've mentioned. There are others as well.

admin · Site Admin Joined: 21 Jun 2005 Posts: 210

I run a qmail-ldap installation for about 10,000 users. Each has 100MB
of quota. I use 2 LDAP servers, 2 qmail servers and have all the
Maildirs stored on a 5.6TB Xserve RAID.

There are a couple of issues you will run into here.

1. Mass storage. FreeBSD doesn't support file systems > 2TB, at least
not that I found decent documentation and support for.

2. Backing up 50,000 Maildirs, where each email is a separate file
requires something custom. I use Bacula, a network backup tool, and I
instruct it to do a tar-gzip of each Maildir before backup. This adds
a bit of overhead, and almost doubles space usage, but it sure beats
backing up millions of little 4K - 80K files!

3. There is a MAJOR bug with maildirsize, the quota file. These quota
files go out of sync a lot. From a year of statistics about 0.1% of
users will likely have out of sync maildirsize files everyday. Who it
happens to seems to be random. I wrote a custom script that runs every
15 minutes to clean up the out of sync maildirsize files.

Other than those issues my qmail-ldap installation runs super stable.
On the two mail servers I have serving up IMAP and POP3, their load
hovers around 0.1 to 0.3 barely anything at all. On my NFS server the
load is about 0.3... it's barely working too.

Hope that was helpful.

Ben.

admin · Site Admin Joined: 21 Jun 2005 Posts: 210

admin · Site Admin Joined: 21 Jun 2005 Posts: 210

See http://www.lifewithqmail.org/ldap/ Maybe you could ask on the
qmail-ldap mailing list Wink

=adriaan=

admin · Site Admin Joined: 21 Jun 2005 Posts: 210

Some possible tutorials to help you on your way are:

QMR (qmail rocks) FreeBSD
http://freebsd.qmailrocks.org/
( Has Mysql, vpopmail, clam-av, spamassin, )

Mail Toaster
http://www.tnpi.biz/internet/mail/toaster/index.shtml
(has mysql)

An honest 50,000 users an mysql implementation might be a little more
hardware intensive then an ldap in the long run so you might want to
drop a mail to freebsd-isp mailing list and ask around there too for
ldap stuff.

Dont forget to if you plan on using maildir as a mail storage solution
then remember that inodes become very important because you WILL run out of them. A solution can be found in the existing man pages, read "man
tuning" before proceeding onto building your server. You might want to
stay away from old school imap software like imap-uw because they lack
the advanced features like quota support that you will need to enforce
quotas for your users.