From: hurf@boa.graphics.cornell.edu (Hurf Sheldon)
Newsgroups: comp.sys.hp
Subject: Re: clusters
Date: 18 Dec 1992 17:32:50 GMT
Organization: Cornell University Program of Computer Graphics
Distribution: world
NNTP-Posting-Host: boa.graphics.cornell.edu
Keywords: cluster

In article <BzFsCM.H5u@bunyip.cc.uq.oz.au> werner@dirac.physics.uq.oz.au writes:
>We are investigating buying several HP7?? snakes and have heard about
>something called a cluster environment for HP workstations.
>Has anybody used this system , what is the implementation (i.e RPC calls?),
>what are the capabilities, what are the management problems, what are the
>limitations, do all the machines have to be identical?

	The HP cluster environment is very nice with few drawbacks. We 
	have a number of 700 systems running under a cluster, each with
	local swap. This works exceedingly well. There are few files that
	are unique to the local systems. All mounts at the server are
	mounts at the clients including nfs and cdroms. (You can only
	mount cdroms at the server - a very minor pain). 
	Some real plusses:
	Network File I/O - Within the cluster you can see full ethernet
	bandwidth (vs nfs at something less than 20% effective) - I don't
	know how they do it but it works very well.
        Adding new systems - Run sam to add a client, enter
	the hardware address from the shipping label, the network id, plug in the
	network and the power cord and turn it on. That's it.
	Updating & patching - Run update on the server - that's it.
	Client hangs (we do a lot of develpment - it happens) - cycle
	power, it's up as soon as the memory check is done. (ala PC's)
	Mail, lpadmin is all done only on the server - essentially
	you only need to admin one machine for n < 30 systems.
	Some gotcha's:
	Don't plan on network swap with very many systems (>3)
	 ( You can swith to/from net swap by editing one file on the server
	 so if you need to run any client diskless it is easily done. )
	Server dies, everybody dies; the clients come around
	so much faster they hang so you have to cycle power on all the
	clients (sub-gotcha - this is so rare you can't remember where all 
	clients are... really)
	Ethernet is much more sensitive to trouble - the old "I've got
	15 secs to reconnect" won't work - more like 2 or 3 sec's tops
	before the client gets abandoned and the server fills the console 
	with error messages (a sub-plus is you can wiggle a bad connector 
	and see an instant error message)
	There can be some subtle misunderstandings because of the context
	dependent file structure but they get pretty obvious after you
	see one or two.
	All in all I reccommend the cluster environment to any hp site
	with more than one system of the same type. I think you would need
	more than one of each type to see any benefit to a 'mixed' cluster
	from a reduced overhead point of view.


-- 
     Hurf Sheldon			 Network: hurf@graphics.cornell.edu
     Program of Computer Graphics	 Phone:   607 255 6713

     580 Eng. Theory Center, Cornell University, Ithaca, N.Y. 14853  
     
From: myers@hpfcso.FC.HP.COM (Bob Myers)
Date: Tue, 15 Dec 1992 19:49:35 GMT
Subject: Re: Snakes "Stereo" output use query
Organization: Hewlett-Packard, Fort Collins, CO, USA