[comp.sys.sgi] IRIS clusters

CMSDS@UGA.CC.UGA.EDU (David Stewart) (12/21/90)

    I am interested in finding out about "clustered" IRISes, that is
a group of IRISes within one logical group (lab).  It is possible that
we may be able to purchase a number of Personal Irises to go along with
our existing 4D/70GT.  My question is:  Should we go with disks or
diskless (they will be linked via FDDI).  What experiences have others
had with similar setups (even those not linked by FDDI).
    The boxes will be spread throughout at least 5 buildings (all linked
by FDDI).
    We haven't had a lot of feedback from our regional sgi office about
this (we consider ourselves very lucky if we can get quotes back from them
within 2 weeks).
    The applications that we would run would be molecular-modeling based:
SYBYL, AMBER, CHARMm, etc.
    Please send your comments to cmsds@uga.cc.uga.edu.

    Thank you in advance for your assistance, and Happy Holidays.

David Stewart

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mg@ (Mike Gigante) (12/21/90)

CMSDS@UGA.CC.UGA.EDU (David Stewart) writes:


>    I am interested in finding out about "clustered" IRISes, that is
>a group of IRISes within one logical group (lab).  It is possible that
>we may be able to purchase a number of Personal Irises to go along with
>our existing 4D/70GT.  My question is:  Should we go with disks or
>diskless (they will be linked via FDDI).  What experiences have others
>had with similar setups (even those not linked by FDDI).

Well, we have 20 SGI machines in a single lab at the moment. It will
split into a group of 10, another of 6 and the rest sprinkled around
sometime next year.

The server is a 220 (SMD), most of the PIs are currently diuskless but I
have abandoned the diskless setup and have already ordered 200Mb system 
disks for most of them.

In my opinion, a diskless PI is a bad idea. With the current setup
(NeWS, the share tree, *symbolic* links fromn the client to share), the 
net traffic from diskless to server is just too high. (I put a sniffer
on the net and watched the traffic). Login from a diskless is ridiculously
slow (this should change once SGI go over to X right?). Paging across the net
is also pretty slow. 

This is particularly bad if you have 8Mb PIs (I have upgraded all PIs to 16Mb)
For example, if you have NeWS, Xsgi, 3 wsh, clock, you aready need to page!!!!!

(SGI: please compile wsh with the shared library if it isn't now!!! It is 
ridiculously large for what it does...)

This is not a flame, merely a comment based on 15 months experience with
diskless. The incremental cost of a 200Mb system disk is *REALLY* worth it.
I would like to emphasise the point *very* strongly.

To be fair, a 16Mb PI with 3.3 is a much more usable diskless machine than
the 8Mb 3.2 machine. However, now that disk prices have come down, the balance
is definately in diskfull's favour.

Mike Gigante
RMIT Advanced Computer Graphics Centre

blbates@AERO4.LARC.NASA.GOV ("Brent L. Bates AAD/TAB MS361 x42854") (01/07/91)

    I recommend that you should NOT go diskLESS.  Have a disk big enough
for all the OS files AND swap space.  We have a file server and diskless
clients.  About 2 months ago, the file server went down for about a month,
which put all our diskless workstations out of commission too.  We are
now in the process of putting disks on ALL the workstations.  Each machine
has all the standard OS files, swap space, and some scratch space.  User
files are on the file server.  That way if the file server goes down we
still have network access and get some work done.  We are also in the
process of considering a second file server.  Half of the user files would
reside on both machines, that way if one server goes down we still have
one server, and important user files on the down machine can be put on the
working server from back up's.  Diskless clients are too costly in the
long run.  We found that out the hard way.
    Hope this helps.
--

	Brent L. Bates
	NASA-Langley Research Center
	M.S. 361
	Hampton, Virginia  23665-5225
	(804) 864-2854
	E-mail: blbates@aero4.larc.nasa.gov or blbates@aero8.larc.nasa.gov