What you need is a real server, a 44P is a workstation, the inner architecture of a true server is quite different, and so I would say the the first question in your choice :
What kind of server (HW) would meet my request...
Then it depend on how much $$$ you are ready to dedicate...
My suggestion would be any server with double SCSI controllers (2 controllers on 2 separate cards...) many NICs, then either you have 2 identical disks inside for the OS and software and you mirror,then add a disk subsystem (SCSI o NAS) ive seen cheap NAS out on the market in RAID5... then maybe an LTO with a backup software