— Storage Horizons Blog —
HDD, Hybrid HDD/SSD, Or All SSD Storage: So Many “Shades Of Grey” That It Is No Wonder People Are Confused!
There is a significant amount of hype out there around all SSD solutions, in the marketplace today, with the likes of Violin, Pure Storage, Nimbus, etc. There is also a lot of hype about some start-ups that put SSD in as cache, along with SATA drives, to be an “all-in-one” box that includes every feature on the planet. But in the end, when building a storage array, then using it, it comes down to price performance and how people think about storage with respect to the rest of the computing application.
While hybrids offer a hedge against decreased quality of service (when heavy usage of applications occur), and all SSD solutions seem to be overkill because of the cost differences between flash and HDD capacity (except for the most demanding of applications), in this day and age, good HDD solutions still fit the bill for most applications. After all, what is the center of the universe—storage or the system/application? (Hint: It is the system/application!)
Applications such as a database, virtualization with multiple applications, VDI, and many others have “signatures” with various types of I/O that make up the “signatures.” They range from sequential read/write, localized random I/O (tight random across a relatively small range of capacity), to very un-localized random I/O (for application metadata or seldom touched pieces of data in the app). These applications have not changed in years and can be tuned to do more or less of each type of I/O, in some instances. However, to use just SATA HDD or just SSD technology to cover these applications seems folly. Anyone can improve capacity by using lots of HDDs to get enough performance to drive an application—while on the other hand, lots of performance can be thrown at an application with lower capacity and at higher costs. The optimum answer is somewhere in the middle. There is a good reason why enterprise HDDs are still used, from 7.2K, 10K, to 15K RPM drives, as well as the reason that enterprise SSD exists, in drive form or a plug-in card. The point is to use them for the right workload and in the right mix.
My conclusion is that a good hybrid storage system, mixing HDD with SSD, provides the best price/performance, as well as the lowest total cost of ownership (TCO). It also provides the most predictable & consistent I/O for applications, regardless of the application, if done right—and it will work across the entire purchased capacity.
However, if someone wants to buy a “SAN in a CAN” like most of the other hybrids that basically put consumer-grade flash in with high capacity and zero I/O drives (along with every feature on the planet), that’s an SMB play, not an enterprise play. These kinds of boxes are very much like large SAN arrays (Ethernet or Fibre Channel) and include features that the applications and operating systems already have, as well.
Then there are the all-SSD arrays. We liken them to “Fishing with Dynamite,” however in some workloads they are very necessary, just not for the broader market of today. The variation between these vendors, as well as features, causes me to pause. Once again, the actual design and implementation of these arrays range from scary to insane (adding features to validate their existence) by saying they are the same price as disk with subjective de-dupe and compression capabilities. Once again, many shades of grey and with features that already exist within operating systems and applications.
This new series of blog, starting in April 2013, will give some insight into hybrids and all-flash arrays and why ISE, with its linear scalability and matched storage management for IT and Cloud, as well as incredible performance and TCO, should be a product that all other products, on the market, are compared against first.