Towers and CD-ROM's

[Don Shields <0006514431@mcimail.com>]

Dear Mike,
Thanks for all your time on LM_NET! I hope I can share a little information on y
 our CD-ROM setup.
First the engineering of the system is probably more important than just the num
 ber of drives.
The "Towers" are just recepticals for the drives, nothing more. Seven drives are
  maximum as one
SCSI controller handles 7 devices. Each tower will then need a SCSI controller.
 Three towers,
three controllers in the server. This is just about the max for most servers as
 you will run out
of interrupts for most SCSI controller types, in fact you might have to limit on
 e of the towers
to 5 or 6 CD-ROMs if you are using SCSI Hard Drives.

 The first hurdle in deciding how many CD-ROMs you can handle will be an analysi
 s of your current
system. What is the speed of the system? 10Base-T at 10 mips? 100Base-T or fiber
 ? Also the number
of nodes and configuration of your hubs to analize the traffic flow (before you
 put in the
CD-ROMs) Check the monitor program on your server to find out current utilizatio
 n of the system.
Remember to increase the size of your server memory for every drive you install
 1/2 meg per drive
is a starting point and 1 meg per drive is not out of line with some configurati
 ons. (You will
need to system cache the drives.)

Finally you need to address the impact of the media your are putting in. If all
 21 drives are
going to be in heavy use by 100 user you can't expect the system to handle the b
 andwidth. If in
fact only 4 or 5 are in heavy use and the rest occasional use or metered use you
  might be able to
handle it.

Sincerely,

Don Shields
Mammoth Unified School District
6514431@mcimail.com