Software helps users consolidate servers

Large businesses are beginning to use software that lets them consolidate applications and operating systems onto as few Intel-based servers as possible, easing administration and lowering costs.

Known as server virtualization, the technology promises to let customers divide the server and create independent environments that can run different applications and operating systems on the partitions or processors of the Intel server. Companies, such as Connectix Corp., SW-Soft and VMware Inc. are providing the software that lets Intel Corp. servers emulate the software partitioning and virtual machine capabilities of bigger Unix servers from Hewlett-Packard Co., IBM Corp. and Sun Microsystems Inc., and mainframes from IBM Corp.

There are two types of server virtualization techniques in Intel machines - virtual machine and virtual server. In a virtual machine environment, multiple operating systems run side by side on the individual processors or partitions of the server. In virtual server environments, one operating system is virtualized across the partitions and processors, where it can run multiple applications. With virtualization software, a customer could run an e-mail application on the Windows partition while running a Web server under Linux, or run several lightweight applications such as calendaring or mail on a Linux virtual server environment. Without server virtualization software, it would be necessary to add servers as the number of applications grew.

The desire to consolidate servers is growing, too. IDC predicts that 75 percent of large corporations will consolidate portions of their servers or storage this year. The research firm says the Windows NT/2000 market will see more than US$1.3 billion spent on consolidation; Linux consolidation will top $232 million. By 2006, consolidation in the Windows NT/2000 market will more than double to $2.7 billion.

"We are trying to reduce the number of overall servers we use," says Randy Robinson, vice president of IT for Unum Provident, the world's largest disability insurance provider, in Chattanooga, Tenn. The company's server farm has grown by 50 percent over the past two years.

"If we have a team that wants to develop an application, typically we will need new servers for development, testing and training," he says. "With virtualization, we can take a two- or four-processor server and create multiple instances of the operating system, which allows us to segment and partition our development, training and testing activities, without having a negative impact on someone else."

Meanwhile, Chris Schuttger, infrastructure architect for TXU Corp., an energy services company in Dallas, is using virtualization software from VMware to better exploit the resources of the bigger IBM servers he is buying.

"As the industry makes faster and faster processors, a customer can buy a single processor machine with a lot of headroom they won't ordinarily use," Shuttger says. "If I can buy a four-processor system that can be partitioned with software like VMware, I get two things - higher processor capacity and the ability to run multiple applications on one piece of hardware."

Virtual machine technology evolved from IBM's 30-year old, virtual-machine operating environment for S/390 or zSeries mainframes. In virtual machines, multiple operating systems such as z/OS, Multiple Virtual Server or Linux on zSeries run as virtual machines, and multiple applications can be intermixed.

VMware's and Connectix's Virtual Server software are examples of virtual machine environments; they let a variety of operating systems share the same server. SW-Soft's Virtuozzo uses the virtual server model; it lets a variety of applications share one operating system.

VMware has two software models. The company's GSX server, which is based on Windows or Linux operating systems, lets Windows, Linux, Solaris x86 or NetWare run in the partitions. Its ESX server is designed for large businesses and is based on a firmware installed on the hardware called Hypervisor, which also is used in IBM's VM products on pSeries Unix and zSeries servers.

Analysts say that while virtual machine software gives customers the versatility to intermix operating systems on the same server, virtualization technology is not without challenges.

"Reallocating resources and workload management are going to be crucial for customers that want to run multi-application environments," says Jamie Gruener, of The Yankee Group. "Customers need to figure which applications get the most priority in terms of memory, CPU and access to disk. If you aren't able to do that in the short term, you won't be successful."

Analysts say that virtualization schemes that rely on an underlying host operating system, such as VMware's GSX server or Connectix's Virtual Server, could slow application performance.

"Any time the virtual machine needs to communicate with an I/O device, it needs to switch context back to the application running atop the host [operating system], so that the host [operating system] can do the I/O," says Gordon Haff, an analyst with Illuminata Inc., in a research note on server virtualization. "This long I/O path and the associated context switches carry with them a significant performance penalty for applications that characterize many server workloads."

VMware will launch a version of its virtualization software in the first half of this year that lets multiple processors compose one virtual machine. SW-Soft is expected to ship a Windows version of its software in the first half of this year; and, Connectix's Virtual Server software, which is in beta-testing now, is scheduled to ship in the first quarter this year.

Pricing for server virtualization software varies widely. SW-Soft charges per megahertz. Software for a four-processor server operating at 1.2 GHz would cost $4,800. VMware sells its ESX Server for $3,750 per dual-processor server.

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