Capacity vs. Performance: A Symbiotic Relationship for NAS By Joan Feu-Gelis On November 7, 2011

When thinking about symbiosis, my first thought takes me to my seventh grade science class; however, symbiosis can be applied to many fields, even network storage. Advancements in tiered storage allow storage administrators to match data to the right media. It can be very effective, but is it efficient? The answer is unequivocally, yes.

Compared to traditional storage, where data is stored on the same media, tiered storage is significantly more efficient. However, efficiency is a relative term and has to be looked at over time. Tiered storage may be efficient today, but in six months data could have grown substantially and what was once the right size storage may not fit any longer. This forces designers to over-design arrays, plan for the possibility that the tier 0 storage may be inadequate or that data may need to come from disks as opposed to SSDs. The primary role of these systems is to store data – a capacity layer. Once additional features are added, including “tiering” software (policies that dictate what goes where), you have a system that, although better than older designs, could benefit from better efficiency. These systems execute multiple processes, processes that can consume inordinate amount of resources and can actually conflict with each other. The primary role of this capacity layer is to store data, but the challenge is that we’re throwing more and more data into the mix, expecting this layer to do more.

While this capacity layer is adequate, imagine having another layer that sits alongside it and complements it. This layer isn’t encumbered with the overhead and duties of storing data; its role is to accelerate data movement with maximum efficiency – a performance layer. By using such a layer, you can be much more efficient in how much capacity layer infrastructure you use. In fact, you’ll probably need much less of it. This performance layer can help you cost effectively scale storage, while delivering performance. And, the payback can come in two ways: it may actually allow work to be completed faster and hence contribute to revenue generation and two; it can reduce costs, capital, power, space, and cooling. And it does this by taking advantage of the NAS that you already have.

In a symbiotic relationship, the performance layer takes on data movement which otherwise could slow down the capacity layer. This allows the capacity layer to focus on storing additional data. Both layers complement each other in maximizing the NAS storage capacity you currently have, while improving performance – something that even my seventh grade science teacher would appreciate.