Virtualization has introduced a HUGE change in how servers are requested and acquired. In many cases, people have begun to think of virtual servers as being a “free” or “cheap” resource that has no lead time in requests and little cost for acquisition. This is very dangerous. Keeping adequate virtual resources available is critical to realizing the value of virtualization, but allowing this “sprawl” of virtual machines to steal these resources can be a serious issue. Replenishing resources for the virtualization environment is not free, so you cannot allow the consumption of those resources to be free.
In some ways, purchasing servers moved from the concept of a server being the large boxed item in the back of the store to being the pack of gum at the check out counter. The large box requires a considerable financial investment to purchase and some logistical considerations to actual get home. You don’t buy these unless you need them, and there is some pain involved that discourages waste in these purchases. The pack of gum, you buy that on impulse on the way out the door, and you grab a few extras for later. No investment, little pain, lots of waste.
I go into this topic in much more detail in my recent SearchServerVirtualization article “Closing the VM sprawl floodgates” at http://searchservervirtualization.techtarget.com/news/column/0,294698,sid94_gci1523796,00.html
Please, come back here after reading this article and leave your comments. This is a topic that just won’t go away. Be looking for a future post on VM Stall, and how it relates to VM Sprawl.