Everybody's looking to save a buck these days, and that fact hasn't been lost on storage vendors, who have been anxious to promote their own reclamation systems, virtualization programs, and other techniques designed to extend the life of storage devices. Virtualization in particular has become widely accepted, and it works--standard storage devices just never make full use of available storage, and virtualization helps you make better use of it.
But how much? You'll find a variety of claims about how much you can increase your storage utilization rate, but in general you should be able to increase utilization by at least 50 percent. Some vendors even offer a utilization guarantee, and this is something worth looking into. Not all storage virtualization vendors offer such a guarantee, and in reality, it's not an absolute necessity if you're convinced the technology is good. At this point, storage virtualization has been refined, we know it works, and it's really not rocket science--and as a result, it's pretty easy for a vendor to offer a guarantee of 50 percent utilization increase. Nonetheless, it's good marketing, and guarantees never hurt, if they're offering.
Does a utilization guarantee weigh in favor of a vendor? Sure. Should you make the utilization guarantee part of your requirements? No. Look at these guarantees critically, and assess how much marketing hype is involved. What specifically does the guarantee involve. For example, if they're offering a guarantee of 50 percent increase in utilization, what's the baseline that 50 percent is being compared against? Sometimes the language of guarantees like this can be vague and meaningless--so take a close look at the details.