> Currently, we have an aging VAXcluster on campus that serves as the
>main student machine for mail, reading news, telnet/ftp, etc. We are
>looking into replacing it with some high-end UNIX machine(s). (Yay!)
> Since every student gets an account, we have around 3000 accounts,
>of which about 1000 are active. Peak use is under 200 users logged in
>at one time.
> What I'm looking for is input on what level system or systems we
>need to replace this. I'm looking for specifics here, brand names,
>numbers, RAM, etc. of comparable systems running elsewhere, since I need
>to write up a proposal.
> So what's your view? How much hardware is enough to handle this
>sort of load?
If it is just a bunch of users, I would look into a Sequent Symmetry
system. At the U of Illinois Champaign-Urbana, one old Sequent S81 (8
386's) supported 160+ users quite well. It was only slow when 180+ users
logged on (like it was swapping -- it probably needed more memory). Current
Sequents are going to be much faster and also run much newer versions of
UNIX. I would give them a call (sorry no phone number) and get some
An alternative would be a few fast processors -- like a DEC AXP 4200 (a
twin 21064 processors) running either OSF/1 or OpenVMS (hey, if the users
refused to migrate, you could always dump UNIX and switch back to VMS...).
In general, I would make sure you got enough memory and an OS that was
designed to support a lot of users.
Sequent: up to 20 486-?? (possibly Pentium available now/soon) processors
(check out competitors like NCR for competitive bids)
SGI: up to 36 R4400-150 processors
DEC: up to 6 21064-200 processors
I like IBM RS/6000's, but I am not sure if they are appropriate for
this use. They do have a multiprocessor system -- Power/4. I am not
familiar with HP's systems except that they handle small-memory FP problems
very well... Another one to look at is Sun's SPARCcenter (up to 20 SPARC
There is a benchmark called AIM Suite III that attempts to measure
multi-user UNIX performance. You might want to get these numbers to narrow
the list of contenders. Here is an old list:
| | +-------Disks
| | |
| | | +----AIM
| | | |
| | | | +-----Max. Thru-put
| | | | | (Jobs/Minute)
| | | | | +---Max. User Load
| | | | | |
| | | | | | +--Utility
| | | | | | | Index (MPH)
Indigo R3000 64M 432M 31.9 312.2 265 49.7
Indigo R4000 64M 432M 71.3 699.1 410 61.6
Indigo R4000 96M 432M 72.1 706.6 485 61.5
DEC 5k/120 64M 665M*3 13.6 132.8 122 26.5
DEC 5k/200 64M 665M*4 14.0 137.6 131 53.2
HP 710C 16M 420M*2 29.6 290.0 180 ?
HP 720CRX 16M 420M*2 35.5 347.7 229 ?
HP 750 64M 1.3G*2 47.1 461.9 337 ?
IBM 320H 64M 400M*2 20.7 202.5 193 30.6
IBM 530H 64M 400M*2 27.9 273.3 244 34.2
IBM 550 128M 400M*2 34.5 338.3 307 48.8
Sun SPARC 2 32M 424M 19.8 193.7 146 27.2
Sun ELC 8M 424M 15.3 149.9 50 27.0
Sun IPX 16M 207M*2 18.3 179.3 128 30.6
I would, however, try to work with a system a little bit to get a feel
that that numbers are not going to provide.
Right now, I am on a DG AViiON 5225 (twin m88100-25 processors) running
DG/UX 5.4. There are about 1500 accounts in /etc/passwd, but no more then
20 logged on users (plus NFS, POP, NNTP, etc clients). I would guess it
could support 30 simultanious, active X11 users. I would guess it could
support 60 or more simultanious, active terminal users. I have never seen
it with that many so I shouldn't really extrapalate...
Benjamin Z. Golds*