[ Cloud Computing ] Re: why virtualization?

I'm not sure of the validity of all your statements.   VMware's multi-core licensing statement does not mention anything above 2-socket machines (at this time accommodating 6-core processors.)  See what happens when you try to license a 4-socket machine (and those are typically the boxes with the most DIMM slots !!)

http://www.vmware.com/download/eula/multicore.html

I don't know ...  This statements is as of September 15th (first day of VMWorld.)  I would be interested in finding out the answer.

Oracle has ALWAYS had byzantine pricing schemes, so yes, for Oracle environments.  You may be better off with a mainframe running Oracle (and I suspect they will need to change their ways eventually.)

Dual cores MAY perform better than quad or hex in SOME CIRCUMSTANCES, but you need to examine architectures such as AMD Opteron where there IS no front-side bus contention,and memory is more NUMA-like.  Intel also, is soon to adopt on-die memory controllers if they have not already.

I would also argue that TCO vs. CAPEX is a valid argument, regardless of how tired people are of hearing it.  Acquisition costs are MINIMAL compared to ongoing maintenance, and especially administration.  Servers are cheap, ESPECIALLY when virtualized.  I find it difficult to argue against virtualization in this day and age.  Of course, I am biased, being a XenServer SE, but customers sure seem to be getting it, and I don't see how cloud providers would be less affected by the economies inherent in this technology.

On Thu, Dec 18, 2008 at 4:11 AM, Mauro TINELLI <tinelli.mauro@gmail.com> wrote:

Jan, you say:

"In a virtualized environments, with sound CPU scheduling, multi-core systems truly allow multiple workloads to consolidate gracefully on single servers."

Not quite since unfortunately today (still):

• as cores/cpu ratio increase performances go down, due to contention on the bus  & clock, etc. Dual-cores may perform globally better than 4+ cores.
• software licensing is a mess, e.g.
  
• Oracle is per core and highest clock are convenient (IBM pSeries may be cheaper than x86!!)
  
• VMware is per Processor, the more cores the cheaper.
  

In conclusion we still depend a lot from the Applications and cpu/mem load associated.

"Blade architectures are an order of magnitude more efficient than traditional 1-U boxes, particularly when it comes to sharing power supplies and cooling fans redundantly.  Unfortunately, they tend to be highly proprietary, but certainly less so than any viable alternative to off-the-shelf Taiwanese parts."

and also when it come to cost per unit and memory scalability the 1U servers are still the winners. In fact as you grow with the number you grow with the CAPEX and that's still the 1st hurdle to  overcome.

Ciao, Mauro