[Dovecot] Storing Dovecot index files on sql

[list at airstreamcomm.net]

We have been communicating with the mailling list on another thread
regarding dotlocking on the dovcot-uidlist over an NFS share, and I was
hoping to get some ideas on whether or not a sql database would be a
suitable location for storing the dovecot index files. Our though process
so far has been that storing the index files on NFS with the maildir has
not worked very effectively when we are using multiple Dovecot servers
(even using sticky IPs in our load balancer), and using local storage is
not possible with a cluster of machines, so we got to thinking about what
type of storage platform would be suitable for these index files that would
provide native locking of the data while multiple servers accessed and
wrote to it. Our question to the community is whether sql storage for index
files has ever been considered, what issues would this introduce, and if
it's even feasible? 

Thanks everyone! 

Michael