Good, Good, Good…Good Vibrations

Its summertime, time for a little Beach Boys? No, Good Vibrations is the beginning of a series of entries that I will be posting on increasing physical hard drive unit life. In recent briefings, manufacturers like Copan Systems and Xiotech have been raising the issue on the impact of drive vibration. While I was aware of drive vibration, it is not discussed much, so I decided to take a deeper dive.Most drive failures that occur in the modern day storage system are not failures at all. In fact, some drive manufacturers report as much as 70% of the drives returned to them are working perfectly fine. So what is causing the false failures and what is causing the real failures?

The first couple of entries are going to examine drive vibration and in this case there are no good vibrations, only bad (my apologies to the Boy's). When a drive spins ,it vibrates, which is not a major problem when there is one of them, but when you start to really stack them into array shelves it can really cause problems and eventually failures.

The most common problem is in the shelf itself. Drive shelves are designed with failure in mind and, as a result, they get what they are designed for; failure. First, all the drives are mounted the same direction; they are tightly packed in a 3U drive enclosure with drives spinning in the same direction and with their actuators operating in the same direction.

The challenge with this is that, because of the tight packaging, they lack firmness to help minimize the vibration. The drive cages themselves amplify the problem because they are looser in the front than they are in the back. Because they are all mounted and spinning in the same direction and their actuators are moving in same direction, the drives create harmonic vibrations and enclosure torque.

Vibration is real and external storage systems cause more of it. In our next entry we will look at the effects of drive vibration and why you should care.

George Crump is founder of Storage Switzerland, an analyst firm focused on the virtualization and storage marketplaces. It provides strategic consulting and analysis to storage users, suppliers, and integrators. An industry veteran of more than 25 years, Crump has held engineering and sales positions at various IT industry manufacturers and integrators. Prior to Storage Switzerland, he was CTO at one of the nation's largest integrators.