storing mail across several cyrus partitions

[Artem Bokhan]

Hello.

Can anybody estimate amount of work needed to make messages of a single 
user (mailbox) could be stored across several cyrus partitions? Is it 
easy to realize or some fundamental work is needed? Can anybody give 
comments?

I would like to make extendable (by size) user mailboxes, but I don't 
want to move accounts over partitions when disk space becomes low, 
instead I want to attach new storages and store new mail there.