VMware’s planned acquisition of Virsto will add yet another component to its software-defined data center initiative. This purchase of course affects the vendor's desktop and server virtualization portfolio by adding improved storage.
VMware-Virsto acquisition: What Virsto has to offer
Virsto's technology is designed to do thin provisioning better than out-of-box solutions from the big vendors, while adding caching and optimization for different types of storage. The software works with any block-based storage back end -- in any combination. That means VDI admins can have different tiers for different purposes, like a solid-state drive (SSD) tier for super-fast, high I/O data, and a spinning tier for more static data.
VMware is playing leapfrog with Microsoft here.
There are two components to Virsto: a virtual appliance and a hypervisor component that installs directly onto the hypervisor. The virtual appliance does the dirty work by appearing as a Network File System (NFS) share to the hypervisor and connecting to the back-end storage tiers. Requests to create virtual disk files are instead used to create Virsto vDisks, which appear as VMDKs to the hypervisor, but are able to be optimized by Virsto's technology.
For instance, writes to the VMDK are sequentially dumped into a log by Virsto, which happens very fast, and then committed back to disk. The result is that the virtual machines (VMs) don't wait very long for any operation to complete because they let Virsto do the hard work for them.
Microsoft's leaps lead to Virsto acquisition
VMware has some level of storage optimization, but it also needs to focus on the entire platform. Because of this, a cottage industry has appeared with storage optimization companies trying to build on what VMware and others have already created.
Companies such as Virsto, Atlantis, Nexenta and a host of others have products that are designed to enhance VM storage performance. We see this kind of technology more in the desktop virtualization space because the I/O requirements are much different than that of servers. Until recently, VMware was happy with this arrangement. It had the best hypervisor, and if someone needed better storage performance VMware was happy to let customers look at one of its partners.
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That started to change with Microsoft's Hyper-V 3 and Windows Server 2012. VMware no longer enjoys the copious lead it once had in nearly all aspects of platform virtualization. Microsoft is nipping at its heels, and in some respects, has either drawn equal or added features that vSphere doesn't have. For instance, Microsoft could be considered ahead of the curve with a feature called Storage Spaces.
You may know Storage Spaces from Windows 8, where it can group disparate disks into a storage array with a calculated level of redundancy despite the disks not being identical (or even connected in the same way). Windows Server 2012 and Hyper-V use Storage Spaces, and when you begin to see how the feature lets you create and group storage by tiers, you can see where VMware might be going with Virsto.
Of course, VMware is playing leapfrog with Microsoft here, because VMware didn't just add the ability to aggregate different kinds of storage into addressable tiers; it also enhanced its storage performance and thin provisioning capabilities. That's because VMware no longer enjoys a lap lead in the hypervisor race.
It's interesting to note that Virsto also supports Hyper-V and XenServer, but I can't imagine that capability continuing into new versions of the software. Expect to see VMware honor current agreements for support but eliminate the capabilities from future versions. Virsto was tied very closely to VMware, so look for integration fairly soon after the deal closes, which is expected to happen by the end of March.