[Dovecot] Please help to make decision

[Tigran Petrosyan]

Hi
We are going to implement the "Dovecot" for 1 million users. We are going
to use more than 100T storage space. Now we examine 2 solutions NFS or GFS2
via (Fibre Channel storage).
Can someone help to make decision? What kind of storage solution we can use
to achieve good performance and scalability.