failover+balancing options

[Patrick Tracanelli]

Hello,

I have a problem and could not find a solution yet. I would like to
hear you opinion.

I have 2 machines, machine A and machine B. They are mail servers
serving with Maildir. I need to find out a solution where I can do
balancing between server A and B while in production, and, if one of
the nodes get down, only the other one will do the work of both.

The main problem I find is a solution regarding the information (data
stored). Right now I have it running with NFS on a third machine,
machine C for example. I know machine C is a SPOF but it is
acceptable.

The big problem is performance. NFS is going away on huge load.

I did ggate0+local disc RAID 1 with gmirror. Sincronization on writing
works perfectly but I can not mount the same disk locally while
exporting it via ggated. Why cant I mount it? Anyone knows? If I
could, eliminating the SPOF would be very easy. Performance would be
great too because ggated performance is way better than NFS on this
kind of operations, specially because READ operations can be done on a
local disk (priority configured via gmirror).

Any idea on how to setup this enviroment?