[DRBD-user] Sendmail and drbd config question

Diego Julian Remolina dijuremo at ibb.gatech.edu
Tue Jul 19 22:34:47 CEST 2005

Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.

> I'm happy to assume that a harddisk failure could cause loss of mail,
> and drbd could be used to manage that risk, but sendmail spools
> can't be shared (?) so that means two different spools.

I use sendmail to deliver to cyrus imap, Cyrus Imap over NFS is totally out of 
the question as mentioned in the Cyrus imap howto. The reason to use drbd is 
primarily cyrus imap and not really sendmail; but since sendmail is what 
delivers to cyrus, then I also need sendmail to be part of the drbd.

> I'm not worrying about any other scenario just now,
> but I'm always happy to hear horror stories :)
> In the failover case you would want to be able to run the queue in
> the failed-over spool.  The worst case might be a split-brain leading
> to a double delivery, and that's allowed anyway.

I have /dev/drbd0 mounted on /export and then I have the sendmail queue in
/export/var/spool/mqueue, so if the primary dies, the secondary becomes 
primary and has control over the spool.

> If you do some sort of VM failover then thati could take care of the
> queue running.
> Other than that I see no obvious reason not to make the setup as
> symetrical as possible.  Run sendmail simlutaneously on the two servers.
> If you need drbd'ed local delivery, then deliver by nfs to maildir
> from the secondary.  Make a decision about syslogging. Anything else ?

> What parameters do you want to make different?

When secondary is running by itself, I want to be able to send e-mail out to 
get reports from things like cron, logwatch, etc, which does not work unless 
sendmail is running with at least the default config.

> People talk about cyrus in the context of mail clusters as well,
> but I don't profess to know anything about it.

Cyrus imap is very cool because of its features.  Some of them:
- Mailbox ACLs so you can make common mailboxes, allow read ony access to 
certain users to other user's mailboxes to avoid the common problem of 
password sharing.
- Supports Kerberos auths (GSSAPI)
- Supports quotas.
- Single Instance Store (If one message goes to many recipients then it only 
creates one message and hard links to the other users mailboxes).

Check http://asg.web.cmu.edu/cyrus/download/imapd/overview.html

I actually want Cyrus imap to be the HA service.  However since sendmail is 
what delivers mail to cyrus, then I have to configure sendmail to only start 
with the domain config to deliver to cyrus on the server acting as primary 
cyrus imap.  Since NFS is out of the question as mentioned in the cyrus 
website, I cannot have both servers running sendmail at the same time and 
delivering to cyrus imap both natively and through nfs.

> I'm not doing this at the moment, but I may heading this way.
> I'd be very interested in knowing what setup you end up with.
I have decent install notes including installing cyrus, clamd, mimedefang, all 
perl modules and just need to finish configuring sendmail to finish up my 
notes.  All of the notes are for RHEL4.  I will be willing to e-mail them to 


> > I am currently running sendmail with the mimedefang milter, checking
> > viruses with clamd and tagging spam with spamassassin and then
> > deliverying mail to Cyrus imapd.  All of these services are started
> > through heartbeat on the haresources file.
> I also have spamassassin, and a question on the back-burner is how to share
> information across bayes DBs.
> Regards,
> Paddy

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