Microsoft’s Hyper-V virtualization offering was released last month, and with it came a raft of announcements from storage and data protection software vendors offering support for the new hypervisor.
Why the interest from these companies in Hyper-V? After all, VMware dominates the virtualization space, with an 82 percent market share among European companies that use virtualization, according to a recent survey carried out by research firm IDC, and a similar market share in North America and the rest of the world.
The answer is that the popularity of virtualization is set to explode over the coming months, with 52 percent of companies not using the technology today planning to do so in the next 12 months, according to the same IDC survey.
A significant number of these will likely choose Hyper-V over VMware, because Microsoft excels in getting footholds in markets by giving away products which are not as good as competitive offerings, but are “good enough.” Hyper-V comes bundled with Server 2008 for just $28, making it an extremely attractive way for companies to experiment with virtualization.
But any company choosing Hyper-V over VMware is likely to face a number of storage challenges in the short to medium term at least. That’s partly because VMware is more technically advanced, and partly because it’s a relatively mature product with established relationships and certifications with numerous storage vendors. The range of partnerships and solutions that are Hyper-V certified won’t be anything as broad as those that VMware can boast any time soon.
As you’d expect, VMware is particularly keen to advertise the differences between its own hypervisor and Microsoft’s, saying that because Hyper-V lacks an integrated cluster file system, storage provisioning is much more complex.
“To enable independent migration and failover of virtual machines with Microsoft Hyper-V, one storage LUN must be dedicated to each virtual machine. That quickly becomes a storage administration nightmare when new VMs are provisioned,” the company said in a blog posting last month.
While you wouldn’t expect VMware to take any other line, no one would disagree that Hyper-V is relatively weak when it comes down to a feature comparison. “Hyper-V is really very basic at the moment,” said Roy Illsley, senior research analyst at Butler Group. “I think to begin with, Microsoft will be aiming at the SMB marketplace because storage partnerships are not so relevant there, and customers will only be doing basic virtualization activities like server consolidation.”
One important feature that VMware has but Hyper-V lacks is VMotion, which enables companies to move a virtual machine — a file stored on some storage system — from one physical host to another without having to stop and restart the virtual machine during the move. Although Microsoft has a feature called Quick Migration, this involves the virtual machine being taken offline during the move, which is not an option in some environments.
Perhaps more important to storage professionals is the VMware Storage VMotion feature. This enables administrators to perform the live migration of virtual machine disk files across storage arrays while the virtual machine continues to run uninterrupted on the same physical server. This makes it more practical to carry out storage migrations when new arrays are purchased or leased, and to optimize the use of existing storage resources and reduce storage I/O bottlenecks. At present Microsoft has no equivalent to that.
Citrix May Play Big Role
Perhaps the most general concern for storage administrators in larger organizations is a perceived lack of partnerships between Microsoft and storage vendors when it comes to Hyper-V. If you can’t be sure that Microsoft’s hypervisor will play nicely with all the storage scenarios you have in mind, but you know that VMware will and is certified to do so, then that’s a significant point in VMware’s favor.
Illsley believes that this stumbling block will disappear over the coming year or so, thanks in part to Citrix Systems (NASDAQ: CTXS), Microsoft’s ally in remote desktop and virtualization technology. Citrix’s XenServer virtualization solution, which is built on the open source Xen hypervisor, is compatible with Hyper-V, to the extent that virtual machines running in a XenServer environment will run on Hyper-V and vice versa.
So how does the relationship with Citrix help?
“I think that behind the scenes, Citrix has been putting a lot of partnerships in place with storage vendors,” said Illsley. “Perhaps Microsoft isn’t overtly making partnerships, but it is probably sitting in on the partnership meetings. Citrix will hand them over to Microsoft in the longer term because I don’t think Citrix see themselves in the virtual machine space longer-term. They will leave it to VMware and Microsoft.”
Among the Hyper-V partnerships that have been established so far is one with Double-Take Software. Double-Take (NASDAQ: DBTK) has extended Hyper-V compatibility to its GeoCluster product. While Microsoft can’t offer an equivalent to VMotion, GeoCluster enhances Quick Migration so that administrators can migrate virtual machines from one location to a physically remote location over a WAN. The company also supplies Hyper-V compatible physical-to-virtual and virtual-to-virtual replication and failover software. Another partnership that was announced in June is with NetApp (NASDAQ: NTAP), which is providing storage management and virtualized storage software that works with Hyper-V.
Longer term, it’s impossible to ignore Hyper-V as a serious competitor to VMware — a fact that won’t be lost on storage vendors and management software makers. That said, it will be interesting to see what EMC (NYSE: EMC), VMware’s parent company, will do to make its storage products work with Hyper-V.
What seems almost certain, though, is that while early adopters will face numerous challenges when it comes to storage, many will disappear over the next 12-18 months, as Microsoft adds new features to Hyper-V and partners fill in the functionality and compatibility gaps.