[ClusterLabs] Data location

[Seb]

Hi,


I'm new to clustering. My purpose is to replace our current server (web, 
mail received and sent, mailing lists, FTP) with an active/passive cluster 
in order to minimize the downtime.

I've read the "Clusters from Scratch" guide, which seems like a good 
starting point (thanks to the authors). The guide does not talk much of 
the data that is used by the services, though.

For instance, what should be done with the emails received on the primary 
node? For the email service to keep working when the primary node fails, 
the emails should be replicated in real time on the secondary node. On my 
Debian box they are stored in /var/mail. From the guide, my understanding 
is that /var/mail should then be located on the partition that is shared 
between nodes through DRBD. Is this the way to go? Should all of /var be 
on the shared partition, perhaps through a symlink?

What about colder data, such as Apache's conf files for enabled websites?
Should they be on the shared partition, or synchronised by hand? Should 
all of /etc be on the shared partition?


Many thanks for your guidance!

Sébastien.