[OpenAFS] Holy Grail of High Availability

[Chris Dos]

I'm been looking at distributed files systems lately and I may have been 
under the wrong impression that OpenAFS or Coda could be the Holy Grail 
for High Availability for the hosting company that I work for.  The part 
that worries me right now is the server replication.  According to the 
documentation that I've been reading, the server replication is only 
good for volumes that don't see many files changing.  So, replicating a 
database such as Oracle or MySQL that changes data often would be a bad 
idea, but web sites or mail might be good?  Would it replcate the entire 
changed file, or just the pieces of the file that has changed.  I'm 
looking at putting three high end terabyte servers next to each via 
Gigabit Ethernet, and having replication take place.  Would the 
replicants be read only?  So all the write changes still have to take 
place to one server.  If that server goes down, will write changes go to 
a server that is still up and running.  Also, how does the client know 
which server go to if there are three servers with identical data on the 
same subnet?  Is there any type of load balancing going on to help 
distribute the load?

Am I totally off my rocker in thinking AFS might be able to provide all 
these things?  And if I am loony in thinking AFS or another distributed 
file system might be my holy grail, are there any other alternatives I 
should be looking at?

Thank you for any insight you might be able to provide.  I sincerely 
appreciate it.

Chris Dos