Justifying storage staffing levels at budget time can be a stressful exercise for the storage manager. Educating both technical and financial managers in the intricacies and criticalities of cost-effective storage management can be a challenge. Of course, at budget time, both technical and financial management are also stressed as they attempt to make the calculations and tradeoffs needed to craft the new year's budget. This environment requires solid empirical metrics relating storage staffing to visible activities. The days of how many system administrators can dance on a gigabyte are long gone, as are management tolerances for emotive pleas for relief. If you could do it last year with "x" staff, why can't it be done this year with "x" staff?
So, how many employees are required per terabyte? The reality is that staffing per terabyte is almost meaningless. A more pertinent basis for determining storage administration staffing requirements is to understand the number and complexity of daily activities required of the storage administration staff, as well as understanding the number of technologies they must support. It is unreasonable to expect staff to be competent in more than three of today's complex technologies.
A good place to start is with a model. Create a spreadsheet that reflects the impact of three groups of key attributes: technology, transaction and complexity factors.
Technology factors cover the key technologies in use that require significant training and/or apprenticeship. Examples include the storage array technologies deployed, as well as the storage management software deployed to control the hardware technologies. Make an assumption about how many technologies a staffer can master at the day-to-day administration level. It is probably going to be two or three. So, with this in mind, if there are nine technologies deployed, you will need three storage staffers.
Now, let's look at transaction factors. This involves identifying the day-to-day tasks that are required of the storage staff. Estimate the time to complete these tasks based on your observations or operational metrics of the transaction activities. Examples here might include activities such as a simple provisioning expansion, a new server coming online or a new storage array arriving.
Finally, you need to consider complexity factors. Complexity involves determining those factors that impact a storage administrator's need for skills and the time needed to execute a task. Examples of complexity factors might include the number of server platform technologies attached, the number of actual servers attached, the number of interswitch links and the number of discrete arrays. Complexity factors might also include the degree of documentation available for repeatable execution and the tools available to manage the execution.
Dick Benton is a principle consultant at GlassHouse Technologies Inc.