Most storage systems that you buy from major manufacturers are really storage software running on servers designed specifically to house a lot of hard disk or flash solid state drives (SSD). They have a lot in common with software-defined storage and there is almost nothing that would prevent these vendors from virtualizing their storage software and also being software defined.
Storage systems can differ in a few ways from SDS. First, they can provide newer and more innovative services. To some extent, though, this is just out-developing SDS vendors with better software. Storage system vendors do have a lead in the basic core services they provide today and that might give them an advantage in developing the next generation of storage services. They might also have an advantage in knowing what lies beneath their software.
[ Want more on software-defined storage? Read Software-Defined Storage: A Buzzword Worth Examining. ]
For example, as I discussed in "Primary Storage Deduplication and SSD," a flash vendor might decide it's worth investing in deduplication technology because they have IOPS to spare and expense to eliminate. A software-defined storage manufacturer would not have this advantage and might not invest in primary storage deduplication.
The key difference between SDS and storage systems is the level of assembly required. As I mentioned in my earlier column, software-defined storage has a "kit" nature to it and the IT designer has to do the integration work between the storage software and the physical hardware. A storage system essentially has that work done ahead of time. While SDS wears its "kit" nature as a badge of honor, most storage systems pride themselves on their turnkey nature.
With a storage system, you know in advance that everything within that system is designed or at least has been tested to work together. Also, support is greatly simplified -- if one vendor provides most of the storage infrastructure, it is liable for making it all work. For the under-staffed IT department these are welcomed advantages over software-defined storage.
For these reasons I think many data centers will continue to invest in turnkey, value-added storage systems, not go the roll-your-own route. But, as we will discuss in our upcoming webinar, "Designing a Cost Effective Solid State Hyperscale Data Center," there will be a measurable number of data centers that will take this do-it-yourself approach to storage. The appeal of reduced costs and potentially greater scale might be too much to turn down.
If this transition occurs on a larger scale than what I predict, then all is still not lost for the lead storage-system vendors -- they could easily virtualize their own offering and lay some claim to being software defined.
Next time I'll talk about how this would be especially easy for storage system companies that are also large server companies. (Three guesses who I'm talking about.) These companies all have struggled lately and I think part of their challenge is they are not leveraging some of their greatest asset: the servers they build.