Storage Virtualization For HyperV
Virsto Software has created a software solution that provides complete and advanced storage services for Microsoft HyperV environments. These environments, like the other server virtualization environments, are pushing storage to the breaking point and storage management issues are often cited as one of the key causes of virtualization stall. This is where virtualization projects start with great success but as they scale risks associated with storage infrastructure stop the project in its tracks. Virsto may be a solution to this problem.
Friday, February 11, 2011
Briefing Note
George Crump, Senior Analyst
Virsto Software is a client of Storage Switzerland
Virsto is a software only storage virtualization solution which means it runs within the HyperV environment and does not require specialized hardware. It also means that it can support a wide range of storage systems at the same time and is an excellent example of data services leaving the storage controller that we will discuss in our upcoming webinar with Nexsan.
Virsto inserts itself between the virtual machines and the hypervisor and presents virtual hard disks to the virtual machines. It then communicates with the hypervisor which communicates with the physical disks. Virsto differentiates itself in its I/O operations. All virtual disk writes are written to a small shared storage area. Think of this similar to transaction logs. The writes are then asynchronously de-staged to the actual hard disks. For reads Virtso creates maps to the data and when needed that data is read from either the log space or the actual disks.
The advantage of organizing the writes in this manner provides Virsto the ability to deliver better performance than locally attached fixed disks with all the advantages of dynamic disks. This includes thin provisioning, which many administrators used to avoid. Virsto as a result of this process makes snapshots more efficient than Microsofts’ own built in capability. Despite all this optimization Virsto remains compatible with the standard HyperV capabilities like Quick Migration, Live Migration, Windows Server Failover Clustering as well as the Microsoft System Center tools (WMI, MMC, VMM, VSS and DPM).
Virsto claims that its process actually improves storage performance in these environments by as much as 3X without changing hardware. Capacity is reduced thanks to practical use of thin provisioning and snapshots are instantaneous with almost no performance impact nor initial capacity impact. HyperV is just the first step for Virsto, they will also be adding VMware and Citrix Xen support in the future.
Storage Swiss Take
Virsto is an excellent example of storage services moving off of the storage devices and closer to the hypervisor. This trend could be a big positive for customers by allowing them to make storage hardware decisions independent of storage software decisions. Interestingly it does mean that storage hardware vendors are going to have to get back to the basics of making solid performing, reliable and efficient storage systems that are uniquely theirs. Virsto also makes HyperV more relevant and capable. They may by themselves cause a data center to more strongly consider HyperV than they did in the past.
