Re: openMosix vs KVM, Xen,...et al

g4sra wrote:
> I have bit my tongue long enough. openMosix never did have, does not, 
> (and as far as I can predict the future) ever will, have anything to do 
> with Virtualization (even though that may have been the original 
> motivation).

Hmm... [donning my best flame-proof underpants] I thought openMosix was 
actually the inverse of 'virtualisation'?

In my naive interpretation, openMosix does what SMP does but uses a 
slower interconnect. Migration of processes between openMosix nodes is 
analagous to migration of processes between SMP processors. In that 
respect, I can understand why Moshe said the advent of (very) cheap SMP 
systems makes it less attractive to spend time building and supporting 
openMosix clusters with 'small' numbers of uniprocessor PC's.

However, I've built a 92-node COTS Beowulf for a fraction of the cost of 
a 'large' SMP computer and I think there is still a lot of life left in 
openMosix. I, for one, will continue using openMosix unless the project 
fragments into internecine disputes about 'what' openMosix is. I guess 
the MOSIX2 developers are smiling to themselves about all this, and 
getting on with their already credible 2.6 kernel and x86_64 support. 
I'd use MOSIX2 now if it was GPL, but that's why we've got openMosix...

> Those knowledgeable on KVM should read up on openMosix, and 
> you will understand why I say what I do.  Any tools written to be 
> compatible with both openMosix and KVM will be nothing more than a 
> bodged compromise, if you want to run that type of software, talk to Bill.

100% agree!

> If you insist on buzzword usage, change "Virtualization" to "Virtual", 
> as a simplistic (and incorrect) view, openMosix provides the capability 
> of having "Virtual CPU's". This persistent lumping in of openMosix with 
> Virtualization does nothing but confuse newcomers and cloud the real 
> openMosix issues. (Somebody demo me standard XP sitting on a straight 
> openMosix kernel and I will eat my words :>).

Hey, we all use 'virtual' machines - The physical address space on most 
'real' systems is not linear. It just looks that way to the CPU because 
of 'virtualisation', and it's the microcode that makes the CPU look like 
an x86/x86_64 etc.

What bothers me is more fundamental: The shift away from 'distributed' 
computing to traditional 'centralised' computing. Virtualisation is a 
step back into the dark ages of mainframe computing where one BIG 
machine is made to look like lots of little ones, and the data centre 
dictate to the users what they are allowed to do and when, with their 
0.001% of available 'mill' time and 0.001%MB of disk quota :-(

I'd rather have my own collection of little machines thank you, which I 
can add to and scale the solution to the task. I can also avoid having 
to make the case for my share of massive expenditure on centralised 
resources that can't be incrementally upgraded. I use openMosix because 
it gives me freedom, in the GNU sense, to do the job I want to and to do 
the job cost-effectively. My experience of openMosix has been excellent.

	Tony.
-- 
Dr. A.J.Travis,                     |  mailto:[email protected]
Rowett Research Institute,          |    http://www.rri.sari.ac.uk/~ajt
Greenburn Road, Bucksburn,          |   phone:+44 (0)1224 712751
Aberdeen AB21 9SB, Scotland, UK.    |     fax:+44 (0)1224 716687

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