Hardware opinion sought - Sun X4500

[Qin Li]

We are thinking of two Sun's Thumper X4500 servers for a fork lifting
upgrade to our IMAP servers. The x4500 is relatively new but a few
reports on the Internet gave it a thumb up, particularly on the use of
ZFS and IOPS of RAIDZ. 

Mail is one of the application cited by Sun for such a box. We have
about 30k users with various size of mailboxes. Any experience or
opinion regarding the use of such hardware for IMAP server will be
helpful to us.

Qin