Solid state drives (SSDs) have fundamentally changed the conversation around storage performance essentially supplanting hard disk drives (HDDs) as the storage media of choice for high performance in storage arrays. However HDDs are far from dead as they remain the preferred storage media for organizations to store their data long term by balancing cost and performance very well. It is as HDDs transition to this role that DCIG has observed some interesting trends in terms of how storage arrays are adapting to support HDDs since optimizing them for performance is no longer a prerequisite.
There remains a great deal of talk about how flash may someday replace HDDs and render them irrelevant or even obsolete. While that may happen, it is not occurring anytime soon as HDDs still provide levels of performance suitable for the vast majority of data stored and accessed by organizations.
Yet cost is probably the primary reason HDDs remain relevant. Even though flash only consumes about 1/10th to 1/20th of the power of HDDs and generates far less heat, HDDs remain available at a price point that is one-third, one-fifth or even less than comparable amounts of flash capacity. This price gap between flash and HDDs will need to narrow significantly in order for flash to displace HDDs that are used to store archival, backup, general purpose file data, infrequently accessed data and unstructured data which represent how HDDs are largely deployed now.
In light of these persisting use cases for HDDs, DCIG observes a growing number of storage arrays that it refers to as utility storage arrays are either optimized or may be configured entirely for HDDs to satisfy these business use cases. These are highly available, highly reliable storage arrays with low or even very low price points (some well under $200/TB depending upon the amount of storage capacity acquired) that can scale to hold petabytes of capacity.
In these arrays, some of the trends that DCIG sees occurring in these arrays include:
- Flexibility to buy HDDs from sources other than the storage array provider. Probably the worst kept secret in the storage industry is that all storage array providers buy HDDs from one of a few HDD manufacturers. This may result in an HDD costing $800 or more when buying it from the vendor whereas an organization may find essentially the same HDD for $400 or less at many online retailers. This can be irksome at best. While there may be valid reasons to buy certified HDDs from the storage array providers (support, interoperability, etc.), this level of support and availability is not always needed for the data these arrays may store. Storage arrays from providers such as Exablox give organizations this flexibility to buy HDDs from the retailer of their choice and install them in the storage array while still getting support from the storage array provider.
- The steady decline of storage arrays supporting HDDs with SATA interfaces. Probably one of the more unexpected trends in evaluating all-HDD arrays is the drop in the number of arrays that support SATA HDDs. A few years ago, SATA support was viewed as becoming almost a “must-have” feature among midrange arrays. But with the price of high capacity, near-line SAS HDDs now about the same as SATA HDDs, less than 20 percent of arrays support SATA in any form.
- Almost any midrange array is available in some type of an all-HDD configuration a list price below $1000/TB. To get a sub-$1000/TB configuration on some arrays, organizations generally need to make some trade-offs in terms of the HDDs they use to populate the array (such as using 6TB NL 7.2RPM SAS drives.) They may also need to use fewer network ports and lower amounts of cache. Conversely, in researching arrays from multiple vendors, I could easily identify and configure arrays to achieve a $500-$700/TB price point and even identified some arrays in the sub-$200/TB price range when scaling to over 500 TBs. Further, by simply forcing vendors to bid against one another for arrays in all-HDD configurations, I am hearing about vendors offering discounts as much as 70 percent off of their list prices.
- Feature rich. Just because one is looking for an array in an all-HDD configuration does not mean one has to sacrifice on software features. While DCIG’s research is still completing and finalizing on these arrays, it is already apparent that almost all of these arrays offer many of the same features and levels of support that organizations expect. Yet this should not entirely come as a surprise. Many of these arrays were originally developed to host business and mission-critical applications and are now being re-purposed and/or reconfigured to function in this role as utility storage arrays.