Server virtualization is something that everyone seems to be using in the data center (DC) these days. Simply put: we all want to save money, do more with less, utilize our resources better, go green and whatever else might be the catchphrase of the week. Server virtualization helps us to achieve some of these goals by allowing us to share hardware resources of a single physical server (host) among multiple virtualized servers (guests). We can utilize the hardware resources better while keeping the required separation. We also gain the ability to move the guest in case of host failure, a need to increase resource usage or for other reasons.
But the IT environment was not historically designed with such abstractions in mind. The usual setup is one-to-one; that is, one server to one operating system (OS), or one server to one port on a switch. Furthermore, the usual mantra is that “stable = good; change ≠ stable,” and change is much more common in virtual environments than in the classic data center.
Multiple areas of guest mobility may cause issues, but for this article I will focus on problems related to the Storage Area Network (SAN).
Author: Vladimir Stajić, CCSI at NIL Data Communications Ltd