OK, so I will assume you accept that the old model of no prioritization of applications using storage in a storage pool is dumb. I will assume you’ve been reading my blog a bit and you now realize that there is a reason why networking instituted QoS, why airlines have first, business, and economy classes of service. Right? If not start here. If you don’t want to follow another stinking link, then let me summarize: Not all passengers, packets, LUNs or Filesystems are equal, and this inequality allows the Axiom to extract more value for the customer out of the disk drives using QoS for Storage.

So, for the skeptical folks out there, they try and shoot holes in the concept, which is a reasonable thing to do. Let’s pick a favorite, how is the Axiom any better than another system without QoS if for example you are sharing two high priority (call it Premium) LUNs?

To first order, it is not! If all you have is people that want first class tickets, there is no gain in differentiation, because you have defined a problem that allows none. That is simple! So if every Filesystem or LUN is equal, an old style system is just about as good as you can get anyway. Make sense? Well, with Axiom, the data placement on the platter and purposeful automatic striping across different spindles will give you a better and more automatic result than most of our competitors. On the other hand, the differentiation under those conditions is obtainable on any system as long as the data is laid out properly on the disk (manually if you aren’t using an Axiom), and you have enough cache.

OK, so let’s say we don’t define a silly example of two equal, high priority LUNs forced to share spindles. Let’s say we have 10 LUNs, and two are high priority relative to the rest. Let’s also assume that the Axiom is forced to share the spindles that they all reside on (it won’t share them unless it has to). Is this different? How can this be better than a system without QoS since there is sharing going on?

The answer is simple, and clear. To lay it out would be complex, but an example should make it abundantly obvious: Let’s say you are about to walk up to the ticket counter at an airline. Would you rather be in the first class line, or the main cabin? Well, assuming normal distribution of passengers, the answer is obviously first class. We all intuitively know that although you may be sharing the agent(s) with 2 or three other passengers, you aren’t sharing with 100 other passengers. Same applies for Axiom’s QoS. The difference is real, and worth money.

Look, this is not some mumbo jumbo cloud of smoke. Spindles and cache equal IOPS. If you can differentiate the application requirements by IO, capacity, and workload, a storage pool can meet a much wider range of simultaneous application requirements using QoS than without it for a given quantity of spindles. This means that in a world of ever increasing disk drive sizes, Axiom is the architecture that extracts the maximum value out of the storage technology you can afford. Period.

And this, my friends, is worth money - to you.