So what in the hell does this mean anyway? To many, it means using expensive disk for high performance applications, midrange disk storage for mid-performance applications, and low cost SATA desktop drives for archive or disk backup applications. (You may recall this as ILM, HSM, or SRM depending on which vendor’s Flavor-aid you were drinking at the time. (BTW, did you know that despite conventional wisdom it was not in fact Kool-Aid that was ladled out at Jonestown?)

If you have a long memory and been around awhile like me, you can actually recall the days when this meant mainframe and minicomputers (and 8 track tape!). Tiering was by platform, and they were all very expensive relative to today.

Most of our competitors tier by platform, although it is pretty much all open, networked modular arrays. Few people are building closed interface monolithic storage anymore, unless they have a cash cow to milk.(DMoooooX)

So to some, the modern idea of Tiering is allowing different types of disk on the same platform and allowing the storage for less critical applications to be SATA on the same platform that FC disk resides. You can see a lot of confusion in chat rooms and blog posts around this. Tiering on an array – well just about everyone has this don’t they? Sure, if you define it as having SATA and FC disk on the same array. We have finally reached the point where people at companies like NetApps (I know, but I like saying it that way since they are so officially uptight about their damn name) have stopped saying SATA will never make it into the enterprise. Whoopty do!

So to me, Tiering on disk goes much further. For those of you who think I am going to say down to the location on the platter, you’re wrong. Tiering on disk to me means that you don’t have to think about what platter, and define LUNs or Filesystems to reside certain types of disk. Tiering on the array means you have a storage pool, the array picks the type of disk you need out of the pool based on your application requirements. It also means that the system will move or migrate LUNs and File systems based on changing requirements. For those of you who think this is standard, that QoS, Application-Aware, and auto-migration of data from FC to SATA are standard, you need to look again. They are far from standard; in fact they are basically not there unless you buy a Pillar Axiom.

Tiering on disk means you don’t have to buy 2, 3, 4 different platforms to meet disparate needs in your IT shop; you buy one platform that meets those needs out of a disk storage pool according to the application requirements you specify when you set it up. The only thing you need to do is pick some disk resources that encompass the needs of your applications to put into the pool, like SATA 1TB disk, FC 300GB 15K RPM disk to span a wide range of high capacity and high performance for QoS to work with for all your applications.

Why? Efficiency. Utilization is driven up with proper application of a storage pool in your data center. You can use both the capacity and the IOPs of the spindles you own using Axiom instead of one or the other.