Messaing Server High Availability
Greetings
I'm attempting to find the best way to provide high availability and disaster recovery into out mail system, using JSMS of course.
I've thought up a scenario and wanted to shoot it by everyone to get some comments and suggestions. I have no idea if it's even feasible, so if someone knows, let me know please.
Ok, essentially it's this.
There are two JSMS servers, lets call them larry and moe, they are idependent of each other, meaning they have thier own configurations. They are in different locations as well, larry is in say, New York City, and Moe is inBoston. They are still on the same network. Also, larry and moe share the same user/group directory. Both larry and moe have two messages store, lets call them A and B. The stores, A and B, are also bi-directionally replicated between larry and moe. At the filesystem level using some type or mirroring system, think rsync or mirror, or even a backend type system like snapmirror on a filer. At any length, the files contained in the stores are at anytime nearly matching on each server.
Ok, so how to use this.
We do some load balancing, 50% of the users in the directoy have ther store set to A and the other 50% set to B. Then, all the users with store A have the msghost set to Larry, and likewise, all the users using store B are set to moe.
Now for disaster.
Should we for some reason lose a site (power, flooding, storms, secuirty breach) we run a script that magically changes all of the users who msghost is down, to use the msghost that is up. Now, since we were replicating the files, up to the time the site went away, all the user's email should be there as well.
Essentially the end user may notice a short outage while a site goes down, people freak out and the scripts runs, but eventually it will appears as if it was just a fluke to them.
I am considering the obvious, such as, the need for a large pipe to do the replications, fault tolerance in the directory, etc.. etc...
So, is this doable? Are there any caveats to this that I should be aware of. For istance, can one simply copy a mailbox from one server to another and not have to mess with all the DB's and whatnot, or do more files need to be copied or utilities run?
ANY comments, suggestions or rants are very much appreciated.
