we have Sun StorageTek 2530 with 12 600GB 15K drives.

What is best recommended RAID configuration for 200 users enviroment, for quick webmail response and heavy calendar usage? We would need about 2TB of storage space.

I am asking, since we used Zimbra with NAS with SATA RAID6, and we've delays of 2-3 seconds when sending emails from webmail