Hidden Costs of Server Virtualization
In a recent blog
I talked a bit about virtual sprawl and the sometimes counterintuitive economics of server virtualization. Embotics
has put out an interesting white paper on this topic which addresses the question of whether VMs are really "free."
If you're doing server virtualization, the white paper points out that costs will typically cluster around four areas: infrastructure, management systems, server software and administration. For infrastructure, the more VMs, the more processing, memory, storage and networking for applications needed (ka-ching!). Additional software licensing adds to the tally, as well as increased costs for both management and administration (ka-ching again!)
All told, software licensing costs, admin time and the need for more physical servers tend to be the big ticket items. But if you create a VM and then siderail it with no workload, it's still going to contribute to TCO. Embotics talked to its customer base to get some workups on cost. Some IT shops said that anywhere from 30 to 50 percent of VMs were just not being utilized.
How much do these overprovisioned puppies cost? Total licensing (management, applications, OS) was estimated at $1,000 to $3,000 for generic Linux or Windows servers. One customer cited had about $50,000 worth of disk and license costs associated with VMs that were offline for more than three months. A few others came in even higher.
There are other costs as well -- what Embotics calls "soft costs." These include issues such as security problems associated with VMs placed on the wrong host and audit and compliance risks resulting from non-standard provisioning.
I'd love to know what are your experiences with this problem. Comment here or send me an e-mail.
Posted by Tom Valovic on 06/26/2008 at 12:49 PM