Friday was the last day for one of the members of the team I manage at work. It was under good circumstances as he’s relocating and moving on to a new opportunity with new challenges to solve. Jokingly, I tweeted about the team now being in a degraded state as one ‘drive’ has been removed. That idea has kept percolating in my head and I’ve realized that rather than just a cute way to refer to an IT team, it really is accurate.

For the uninitiated, RAID, which stands for Redundant Array of Independent Disks, is a way to combining multiple disks into a larger collection to present one or more larger volumes, increase the performance, and improve the resiliency should one of the drives fail. Here’s an overview of the three primary RAID levels:

RAID 0 combines two or more disks into a larger volume splitting the contents evenly between them. The benefits are increasing the performance to much more than a single drive as well as increasing the overall capacity. The down-side is that if any single drive fails, all of the data is effectively lost.

RAID 1 combines two disks into a pair where data is written to both drives simultaneously. Capacity is no more than a single drive, but you can lose either drive and still have a complete copy of your data.

RAID 5 combines three or more disks where the data is split between the disks but parity data is calculated and also written to the disk. Performance is good as you can interleave reads between the disks. Resiliency is also good as if any single drive fails, the parity data from the remaining disks can be used to compute the data that is missing.

In any IT shop, you have a collection of skills and backgrounds provided by the members of the team as well as the collection of procedures, resources, and responsibilities that the team must manage. If your team is set up in a RAID 0 configuration, the responsibilities are divided between the members. Each member becomes more and more experienced in the skills they cover but can become more of a liability in the ones they do not. Like in RAID 0, if any one is not available, those responsibilities are gone.

Sure, you could have a team more akin to RAID 1 but I can’t think of any manager that would request (or director that would approve) having two people for every task with one acting as a ‘mirror.’

Personally, I try to strike a balance. Dividing the responsibilities between members, playing on their strengths, but ensuring that everyone is familiar enough with the other things the group-as-a-whole does allows for continuity. Sure, documentation can act as your ‘parity’ but it is exceedingly challenging to maintain complete, accurate, and current documentation.

The group is indeed in a degraded state at the moment, but I am happy to say that nothing should get dropped and it hopefully won’t last long. I’m truly fortunate to manage a group of guys skilled enough to take on almost anything thrown at them.