Report after report has found both RISC and Intel servers to be grossly underutilized in many enterprises. In financially flush times, it's often easier to purchase new equipment than to maximize what is already there. When the purse strings tighten, however, the IS department must make do with what it currently has. These days, one increasingly popular way to increase computing power without purchasing additional hardware is to add servers virtually.
During the past year, innovative vendors and an efficiency-hungry IT space have raised the bar on how much can be squeezed from the x86 chipset. Virtualization, with its attempts to squeeze extra performance out of machines by adding virtual components, has been at the heart of these efforts.
But with increased development of a technology comes an increased scope in its definition. As a result, multiple variations on the term "virtual server" have come into play, rendering confusion.
For example, x86 virtualization, which this column will focus on, divides into two rough camps: products that emulate the hardware itself, providing virtual machines, a la those from VMware; and products that duplicate the software, providing a type of virtual server, a la those from SWsoft.
VMware's virtual machine offerings stand out for their complexity and polish. The company is the most commercially successful and is currently the only Windows/Linux-capable x86-based virtualization software on the market. The software is compatible with most 32-bit x86 offerings and runs on NAS devices and SANs. To date, VMware lacks 64-bit and iSCSI support, and despite VMware's lack of comment, it's a safe bet that this will change in the not so distant future.
But VMware has been hard at work staying several steps ahead of its virtual competition. Shortly before this column went to press, Dell announced it would be expanding its partnership with VMware by bundling its PowerEdge server line with VMware's VirtualCenter and ESX servers. "VMotion technology and VirtualCenter capabilities are a great complementary fit with Dell's scale out strategy," said Vice President of Marketing for VMware Michael Mullany, citing VMotion as the piece that should add back the "pooling efficiencies" of scale up.
A move from the debate of scale up vs. scale out seems to be a central component of the company's strategy. VMware co-founder and chief architect Ed Bugnion says that while VMware supports a variety of architecture preferences, such as 4-way, 8-way, and blade, its new VMotion technology will render the processors-per-box question moot. "VMotion allows you to move a server across physical boundaries while it's running," Bugnion said, "so you can use it for workload rebalancing or hardware maintenance."
VMware's innovations come ahead of SWsoft's plans to expand its Linux/Solaris-based Virtuozzo product into the Windows server arena. Virtuozzo has been popular in the hosting community for its low overhead, highly scalable Virtual Private Servers for some time now, and SWsoft is looking to solidify Virtuozzo's standing in the minds and pocketbooks of enterprise IT managers. A Windows offering is in beta, and a full version is expected for public release in mid-April.
At this time, SWsoft Director of Sales Engineering Jack Zubarev sees Virtuozzo distinguishing itself from VMware in its design. "We virtualize the operating system itself, while VMware virtualizes the hardware," Zubarev told ServerWatch. "This approach has much smaller overhead and much higher scalability," he continued, citing overhead of around 3 percent. This allows a very high instance count on the same machine, perfect for the demands of the Web-hosting space. Other Virtuozzo differentiators, according to Zubarev, are the strength of the product's mass management API and 64-bit Itanium support. This shows the vendor's willingness to adapt to the 32-bit/64-bit curve and will likely prove important down the road.
Real-world Virtuozzo deployments vary. According to Zubarev, Web hosting customers typically deploy Virtuozzo on 2-way-based Xeon boxes to keep customer applications separate and the potential for hazardous downtime if 4-way boxes are used. Enterprise customers running internal applications might use 4-way or 8-way boxes, he says, but 8-way boxes still lack comparative cost-effectiveness.
However, hardware limits also apply. SWsoft's operating system emulation approach trades low overhead for operating system dependence; only one type of operating system can run per piece of server hardware, a possible cause concern in hybrid environments.