Talk:Virtual server
Cloud computing
While all cloud computing uses virtualization, not all virtual machines run remotely. Nevertheless, you may find cloud computing, Software as a Service, Platform as a Service, and Infrastructure as a Service useful. Howard C. Berkowitz 21:32, 7 August 2010 (UTC)
Economics
Some of the points I raise are rules of thumb from experience, while others, with a bit of effort, probably can be found in public presentations.
The industry rule of thumb is that in general enterprise computing, servers dedicated to applications, or a carefully selected, set of applications run about 20% CPU utilization. There are some queueing theory (Little's Law, etc.) observations that suggest it can be unwise to load them more heavily than 50-70%, but that 30% wastage is a major economic target. Remember that the virtualization management (i.e., provisioning and such, not the hypervisor) will take some, and that some applications are memory, not CPU bound. I myself wonder if we know if these rules will stay the same with multicore processors.
There might be a cite for it in cloud computing -- it was at USENIX or LISA -- where a Google person said they were fast approaching a point at which power and cooling would cost more than the hardware. Intel was told, at one developer conference, that power consumption was, to many enterprises, more important than raw speed.
When looking at cloud computing, and, for that matter, footprint, do look at blade server and related techniques. With machines designed for efficient cooling, especially chilled water, cooling becomes much more efficient. Indeed, there are cities (e.g., Cambridge MA, and I think Miami FL) that offer chilled water as a municipal utility -- there are enormous economies of scale, but you need quite a bit of cooling requirement to justify your own chiller plant There was a talk at NANOG on the Miami internet exchange point dealing with the economic effects of water cooling. Google is reputed to have moved a number of its data centers out of California to put them in cooler areas. Howard C. Berkowitz 18:10, 13 August 2010 (UTC)