[Dovecot] Design details of high performance dovecot cluster

[JEHERUL]

Dear All,

Currently we are running a mail system for 10000 users each 2GB mailbox. At
present we have 5 mail servers where users mailboxes are distributed almost
uniformly. We have a HP SAN Storage (HP EVA 6400) where mailboxes are
stored. We partition the storage into five vg and each is mounted on the 5
servers. We are using postfix and dovecot.

The system was running fine but currently we  notices high IO load due to
IMAP connection. So we are planning to build a dovecot cluster.

Please suggest some design for the dovecot cluster keeping in mind to our
scenario. (If needed we can buy additional hardware like load balancer).

With Thanks and Regards
-- 
Jeherul Islam
India