Geoff Galitz wrote:
[...]
I think the idea is that MOSIX functionality is more easily developed
and deployed in the form of virtual machines than directly at the kernel
level. There are some trade-offs, of course... more overhead being
chief among them but the virtualization model is clearly the overall
favorite. It sure does beat the heck out of having to track each kernel
individually.
Hello, Geoff.
MOSIX functionality is mainly about load-balancing between independent
kernels, and avoiding severe memory depletion by migrating processes
between kernels. In fact (open)MOSIX implements an SMP-like model, but
with a high-latency interconect (usually GBit ethernet). There is no
need to 'track' kernels, because the oM HPC extension does it for you.
The principle objective of SSI computing is to use many small machines
as if they are one big one. This is the opposite of virtualisation which
uses one (or a few) BIG machines like a lot of small ones. It does this
by virtually separating the kernels. There is some confusion about this
because it *is* very convenient to teach about or develop and test SSI
software on virtual compute nodes if you don't have a lot of real nodes,
but it defeats the purpose of SSI to use this approach in production.
You might be interested to know that one reason Moshe Bar gave when he
announced the end of the openMosix project was that SMP is now so cheap
that SSI clustering less of a factor in computing:
http://sourceforge.net/forum/forum.php?forum_id=715406
I'm not sure I agree - I still find openMosix useful, and I'll continue
using it on our Beowulf here until I find a better alternative.
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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