Virtual Servers Update: VMware vs. Microsoft vs. Xen

3) Falling Prices and Improved Functionality: Prices are coming down and functionality for even the free versions is improving. The free products – and indeed, all of Microsoft's virtual server line – continue to be a great way for enterprises to become familiar with VM technology and to do any evaluations before deploying them into production. Most noticeably Microsoft has announced they will expand their product line with Hyper-V, which will be included in all 64-bit versions of its Windows Server 2008, expected in August. Hyper-V ups the ante considerably, with support for symmetrical multi-processors and larger memory support.

On the paid products, XenServer continues to be the lower-priced spread, offering single-CPU versions and better value when compared to VMware. The latter's prices are now almost comprehendible, an improvement from their obscure complexity of last year. VMware also introduced support for 10 gigabit Ethernet networks and larger memory and disk support with its latest version, and now has more than 700 pre-built virtual "appliances" or virtual disk images that are available as well.

Citrix hasn't stood still either, and boosted the performance of XenServer since acquiring the company last year, especially when it comes to XenServer working with the company's flagship Presentation Server product line. "We recognize that our customers want to run both products to solve dynamic data center problems," says Crosby.

4) Widening Channels: The virtual server channel continues to widen, with more partnerships, agreements, and expertise than ever before. As smaller, specialty companies enter this market, they are looking to cement relationships, expand distribution, and make just about every component in the data center virtualized. "All of the services that do hardware and applications failover, disaster recovery, chargeback, and security will be built into hypervisors and run on VMs," says Susan Davis, the VP of marketing for Egenera, one of the newer specialty virtual software vendors.

"This year is shaping up to be one of the most interesting years ever in enterprise IT infrastructure," says Crosby.

Table: Virtual Server product comparison

	VMware	Microsoft	Xen
Product URL	Vmware.com	Microsoft.com/virtual server	Xensource.com
Free server product	VMware Server	Virtual Server 2005 R2, HyperV Win Server 2008 64 bit	XenServer Express, (Enterprise 30 day eval.)
Paid server products	Infrstructure v3.5 (Starter, Standard, and Enterprise)	None	XenServer Standard, Enterprise, and Platinum Editions
Pricing range paid product	$1640 for two CPUs, includes 1 yr. support contract	Free or included in Windows Server 2008 (64 bit)	$600 - $5000 plus support contract
Host OS (if any)	Server: Windows Server 2003, various Linux Infra v3: bare metal	Windows Server 2003 R2, 2008; XP Pro SP2 or Vista for testing purposes only	Bare metal
Management tools	Lifecycle Manager, VMotion, Storage Vmotion	System Center VM Manager	XenCenter Management Console
Embedded hypervisor product	ESXi supports both AMD and Intel chipsets	None*	Yes
Advantages	Over 700 pre-built appliances Widest selection of guest OS support Wizards galore for install aids	Can run on any IE browser with Internet access Less expensive option Easy cloning of VM images Familiar UI	Open source solution that doesn't require any host OS Lower cost
Disadvantages	Confusing array of pricing and configuration options (2 CPU minimum pricing)	Limited pre-built VHD appliances and just of MS server products	Limited Windows guest OS support

*While Microsoft's offering doesn't have an embedded hypervisor, it does recognize and take advantage of computers with either the AMD or Intel virtualization chipsets.