Alternative storage backend for Dovecot

[Oleksandr Natalenko]

Hi.

We have corporate Dovecot setup with GlusterFS as file storage. We store 
maildirs on GlueterFS share, mounting it via NFS. Mounting share via 
native GlusterFS FUSE client introduces visible performance overhead. 
Also, NFS mount does not provide us with HA.

That's why I have an idea to use GlusterFS C API to access maildirs 
share. I'd like to preserve maildir structure, but get access to it not 
via FS mount point but with GlusterFS C API calls.

I've discovered that Dovecot source tree has src/lib-fs infrastructure 
with fs-posix implemented on top of it. Is that the right place to start 
from? GlusterFS C API calls are POSIX-like, so they could be easily used 
as substitutions for VFS ops. Could such a backend be implemented as 
separate plugin?

Are there any examples of alternative storage backend to look at?

Thanks.

Regards,
   Oleksandr.