Raxco’s Bob Nolan explains the role of the SAN, the storage controller and the VM workflow, how each affects virtualized system performance and what system admins can do to improve slow VMware/Hyper-V performance:
There is no doubt virtualization has brought enormous efficiencies to corporate IT, but better performance is not one of the benefits companies can count on. A survey of IT managers by ZK Research indicated more than 25% of virtualization projects were rolled back to physical servers for performance reasons. That is a 1-in-4 failure rate. Queue contention, disk latency and sluggish virtual machine (VM) performance continue to plague virtualization implementations. Why is it that I/O related performance issues are still an issue as the industry moves steadily to more virtualization and SAN technology?
VMware now recommends an activity that resolves these I/O issues and this blog post explains its importance in depth. To better understand these problems we first examine what is happening at the SAN, controller and virtual machine level and their respective roles in these performance issues.