Connecting a NAS storage to Vertica

Currently we are working on 6 nodes Vertica cluster. Each server supports up to 10 HD disks of 600GB and we can not add more HD to this type of servers. 
with this specification we are not reach the minimum required I/O is 20 MB/s read and write per physical processor core on each node.
Can we connect Vertica to work with NAS storage through fiber channel card?
What is the HP recommendations to work with this type of system configuration?
Can we work with the NAS and the local HD in parallel?