On Mar 22, 2008, at 5:44 AM, Rico Secada wrote:
Hi.
A customer with very limited resources needs to set up a high
available
system running apache, mysql, postfix and dovecot and I have gotten
the
task.
it's doable, but the unanswered question is what do each of these
components have to do with one another? What exactly are you trying to
do?
I have only two Pentium 4 machines at my disposal, and I have begun
researching how to make them work with load balancing and fail safe
operations at the same time. I have one public IP address available.
This would be a CARP component.
I would like to reach a state, if possible, in which load balancing is
performed, but at the same time, if one machine fails, the other will
automatically take over. I believe this setup is also very useful when
deploying updates.
You're screwed on the load balancing without a 3rd system in the mix.
Preferably 4 systems, so you've got failover between the firewalls.
Any advice on how to implement such a setup?
First, figure out what they're asking for. Then separate the problem
in to component issues.
- MySQL master-master replication
- HA Heartbeat (linux-HA is a good start on how to do this)
- Dovecot IMAP with MYSQL as a back end
-- this is usually just for AUTH. Where does dovecot keep its files?
Last I looked, it couldn't shove them in to MySQL, or pull the email
out.
