[ILUG] Beowulf System Assembly

[John Quinn]

> Shane Dempsey wrote:
> > 
> > Any chance of some performance figures.
> 
	Well our newest cluster here outperforms a 4 x 400Mhz CPU 4100
Alphaserver
	with 4Gb of main memory. The cluster was put together for under 1/8
of the price
	of the Alphaserver. 

>  
	>> What about compilation. Is there any stuff that in the BEOWULF
package
	>> that I can use to speed up compilation of a rather huge program.
	>   gnumake has a flag to enable distributed making
	>   the '-j X' where X is the number of jobs to run, '-j' 
	>    on its own lets make have any number of jobs.
	>  The jobs run on either the local machine via fork or on
	>  other machines.  See the make manual for details..
		
		I don't think GNUmake has the facility for forcing remote
compilation.
		The -j option allows you to force local parallel compilation
jobs, which
		is useful with SMP, but in order to execute remote jobs for
a distributed 
		compile you have to either use a wrapper around your
compiler to rexec 
		it with the proper environment. You also need to have your
build directory
		NFS mounted across all the machines doing work for the
distributed compile
		in the cluster. Check out the following if you need to do
distributed compiles
		across a cluster, and you are using GNUmake:
		
		http://www.interlog.com/~gray/doozer.html
		http://www.scri.fsu.edu/~dwyer/dmake.html
	
	
	If you are interested in using a new type of make tool, that is
better at handling
	dependencies, and handles distributed compiles out of the box, check
out
	
	http://bake.werken.com/
	
	

	>> Or would the time taken to pass data across the network not make
	>> distributed compiles worthwhile.
	> with make and an NFS'd disk, should be all right.
	> with an SMP machine and local disk, then you're talking.

	Well with V2.2 NFS has improved significantly, and with a 100Mbit
Hub compiles 
	run pretty well with up to 10 nodes. Above that its worth switching
to a Switch.
	SMP works pretty well up to a certain point, but you are limited by
the number of CPU's
	a motherboard can accomodate.