Am 13.01.2012 00:22, schrieb Paul O'Rorke:
> hmmm - it looks like I may have to re-evaluate this.
>
> Given that this is a HA-Linux list, and that if I understand this correctly
> it is not really designed for multi-site clusters, can anyone suggest a
> more suitable technology? (the server is running CentOS/Exim)
>
For the filesystem part, you may want to look into glusterfs which 
brings a sync mode suitable for slow links.
The rest might not be that hard - you can have separate SMTP servers 
that just separately send mails on a regular basis. The mail receiving 
part is more tricky:
how do you achieve a takeover of the front IP address or DNS name of the 
service? Probably you do not have an IP that you can let freely wander 
from one network to the other (this is how linux-HA normally does a 
takeover in a local network, needing a redundant link between the 
servers for this).
DNS on the other hand can be changed but how long will it take until the 
clients pick up the change?
You might be able to control the local DNS resolution and put in a tweak 
at this point, depending on reachability of the two mail servers, having 
a DNS entry with a short lifetime pointing at a reachable server. But 
perhaps a remote datacenter solution is the cheaper way... note that to 
reach high availability you need to test your setup thoroughly, 
otherwise you will end up with bad things like "split-brain" or unusable 
services besides your hard work.

HTH,
Jakob Curdes

_______________________________________________
Linux-HA mailing list
[email protected]
http://lists.linux-ha.org/mailman/listinfo/linux-ha
See also: http://linux-ha.org/ReportingProblems

Reply via email to