Jumping in:

Our NT ADSM server is "big enough to fit into one [Compaq] rack".
In the rack we get :
        Twin CPU 400 MHz Pentium II server with 512 MBytes memory.
        5 disks in the server - used in RAID 5 format + one hot spare
(although 3 disks mirrored to another 3 would be better for performance
reasons). These hold operating system, page file and the ADSM database and
logs.
        2 racks of 12 x 9.1 GByte disks in each rack. These are used for the
disk cache.
        6 DLT tape library units (we use Overland Data Library Express). We
have 4 DLT 7000 drives and 84 tape slots per library.
        One keyboard.

The only thing we don't fit in the rack is the monitor! There would be room
for one of the new pop-up flat screens, but we haven't actually bought one.
If you are building one of these, pay particular attention to network
through put (we have 4 x 100 MBit ports to 4 different network segments in
the building) and SCSI channels (one to the database disks, one to each of
the disk caches and one differential channel per two DLT drives).

Attached to this system are approximately 40 clients (NT, UNIX, Novell,
Oracle, SQL Server and Exchange).  We reckon that this ADSM server is
capable of storing approximately 4 TBytes of data. Currently we have 900
MByte of file space data on the clients, and just over 3 TBytes of data in
the library.


Regards, Chris