WSJ writes about the increasing sue of virtual machines software:
VMware’s trick is to fool each operating system on a physical machine into thinking it is talking directly to the hardware, when it really is communicating with VMware. Each virtual machine is essentially a changing file that describes what it is doing at that moment.
This can yield dividends for corporate users. Servers are generally dedicated to one task — processing e-mail, for example — and in the era of fast processor chips, their full power often isn’t used. Some studies put the average utilization rate on Intel-compatible servers, which VMware works on, at about 15%.
So four or more virtual machines could run on one server with little performance penalty. That means buying fewer servers. Administrators also can create scores of virtual desktop machines for office workers that actually run on centralized servers.
Prudential UK, a unit of London-based insurer Prudential PLC, decided last year to put some call-center and back-office operations in Bombay, in part to cut costs. But Prudential (which is unrelated to the like-named U.S. insurer) realized that computers in Bombay, more than 4,000 miles from London, couldn’t maintain a quick-enough connection to the insurer’s databases in the home office, says Andy Ruby, head of infrastructure design.
So he left the hardware in Britain. Mr. Ruby set up 800 VMware virtual machines, acting like desktop PCs, running on about 60 servers in Prudential’s data center, where they can quickly connect to databases. The Indian workers sit in front of PCs that are essentially empty shells to display the far-away virtual PCs. While the time lag created by the distance is still there, the virtual machines’ proximity to the database lessens the effect.