[Dovecot] No failover from director to backend?

[list at airstreamcomm.net]

On 10/21/12 2:43 PM, Daniel Parthey wrote:
> Patrick Westenberg wrote:
>> Is there no built in failover mechanism for the director service to
>> handle a backend failure?
> No, the director's job is to keep a hash table and direct
> the connection for each user to its associated backend.
> Currently, there is no built-in backend monitoring.
>
> In order to handle maintenance of backends, you will need the
> poolmon daemon, which enables/disables backends in the director
> depending on their availability:
>
> https://github.com/brandond/poolmon
>
> Regards
> Daniel
Considering the intention of the director was to alleviate locking 
issues in a shared storage environment are there any current solutions 
to improving the scalability/availability of Dovecot by implementing an 
alternative message storage systems such as nosql or maybe object 
storage that could abstract away the complexity of replicating data?  We 
would love to finally have the ability to set our mail cluster on top of 
a storage subsystem that can span multiple geographic regions and do 
away with the NFS backend.