Re: [Xen-users] The future of para-virtualization

[Casey DeLorme <cdelorme@xxxxxxxxx>]

Hello Xinli,

I have limited knowledge on the subject, but I think para-virtualization will continue to exist for a while.

I am a consumer, not an employee for a large company, so I find para-virtualization to be very important for my uses personally.  Not because of the cost of equipment, but because I only want one machine, and I want it to be able to do everything I ask it to with the best performance it can achieve.

To my knowledge not all hardware has a virtualization friendly architecture.  As a result, full virtualization achieves compatibility by using abstraction layers (emulated devices) at the cost of performance for such devices.  I could be wrong, but I believe this is true still for USB, Hard Drives and Network Components.  My understanding of para-virtualized drivers in particular was that they bypass those layers.  It may also be important to keep in mind that operating systems have also advanced alongside hardware, which has eliminated numerous compatibility related migration issues.

I had a rather lengthy discussion a week ago with someone on the topic of virtualization which revolved around reasons we use it.  We concluded that cost is the greatest factor, followed by performance and compatibility.

If a company has enough money, they don't need virtualization.  The truth is most large companies do buy the latest equipment, and generally upgrade all their machines at the same time.  This addresses compatibility issues (Same Machines) as well as performance (Newest Hardware).  In the face of enough money any notion of what type of virtualization is better becomes a pointless debate.  Additionally with enough money you can afford enough machines that you don't need to use virtualization (not that it wouldn't make more sense to use it).

I already gave you my take on performance as a consumer.  It adds more flexibility and greater performance on less "equipment".  "VMware invented virtualization for the x86 platform in the 1990s to address underutilization and other issues, overcoming many challenges in the process."  I have a Core i7 machine and running a single operating system is a clearly not fully utilizing the CPU.

Compatibility in my opinion is entirely dependent on the situation.  For me not that important, but I can see many reasons why this would be important in many settings.

Again, this is my two cents from a limited viewpoint so I look forward to reading what others have to say on the topic.  If I had to pick a specific trend, I think para-virtualization will become less important to large companies, but still be in demand by small businesses and private users.

~Casey

PS - If you are perhaps thinking that because large businesses may not care about para-virtualization that it isn't important enough to keep around, you may want to give this a read:

http://web.sba.gov/faqs/faqIndexAll.cfm?areaid=24

On Fri, Jun 8, 2012 at 11:03 PM, Niu Xinli <niuxinli1989@xxxxxxxxx> wrote:

Hi,
    Para-virtualization outperforms full-virtualization at the cost of compatibility. But as hardware grows more friendly to virtualization, the advantage of para-virtualization has become not so obvious. Instead, the disadvantage has been amplified.  Personally I don't see a future for para-virtualization. Maybe para-virtualization still has an attraction to small companies who want to build virtualized computing environment with low-price or outdated devices. But I want to know the future trend of para-virtualization. Will it come to an end in the near future?

Best Regards,
Xinli

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