When I read my previous post, I got the feeling that I was saying you needed an objectively measurable financial benefit in order to justify using SAN-attached storage. All my experience in IT has shown that you make no progress if you wait for all the questions to be answered. So reading my post got me thinking, how do I decide when I have enough information to move forward?
That reminded me of another recent project I led, where we set up a VMWare farm, then over the course of half a year virtualized over 130 physical servers and created about 70 new virtual servers. With minimal research we had established that VMs were C$380 per month cheaper, based on hard, quantifiable data (floor space lease, power consumption, server lease, and server maintenance). That's a savings of C$76,000 per month.
On top of that, you have all the harder to quantify benefits that the VMWare sales reps will tell you about: faster deployment, higher availability, etc. The nice thing is, you don't need to count those up when you have such an obvious measurable benefit. If fact, even if we had discovered that server management effort had gone up, we could have got another server admin for almost a year (fully loaded cost) for what we saved in a month by virtualizing.
A lot of what we deal with in IT seems to lean in the other direction: The easy-to-count numbers actually argue against a new approach. The value has to be in the intangible benefits. What I'm exploring with the SAN storage case is how to deal with intangible value.