Western Digital is expanding its data center hard drive offerings with the reveal of a 15TB model based on fourth generation HelioSeal and second generation Host Managed SMR (Shingled Magnetic Recording) technology. The new 15 TB Ultrastar DC HC620 is aimed at data center customers doing surveillance, object storage for cloud services, streaming media storage, online backup and archival storage, and other sequential write focused tasks. The 7200 RPM hard drive comes in SATA (6Gbps) or SAS (12Gbps) flavors, but is not a direct drop-in replacement for just any drive as it works with host managed SMR to optimize how data is written to the drive which needs to be sequentially to get any amount of decent performance out of it. Random performance (writes in particular) isn’t great in other words, but it does offer up to 31% lower idle watts/TB than prior generation drives while delivering respectable (for mechanical drives) sequential performance and areal density with 900TB of storage being able to fit in a 40U (60-unit) rack or 40TB more compared to using 14TB drives
Western Digital’s 15 TB DC HC620 (PDF)is a 7200 RPM hard drive with a 512 MB buffer. It is rated at 255 MB/s sustained transfer rates, 4.16 ms average latency, and 7.7ms read and 12ms write seek times. Further, the datacenter focused drives are rated for 550TB per year with a 2.5 million hour MTBF and a five year warranty.
While enthusiasts will not be using these new SMR drives, they may well be being used by the various cloud service providers and their services that end users take advantage of. It is interesting to see that shingled magnetic recording is still being developed and the increasing amount of data that is able to be crammed into the same 3.5-inch hard drive form factor. I am looking forward to future technologies like MAMR and HAMR as well to see just how far spinning rust can be pushed. While end users are enjoying the speed of solid state storage, hard drives are still alive and well in the data center thanks to TCO (total cost of ownership) and TB/watt/area metrics and the drive to optimize them being paramount. According to Western Digital, global data storage demands are going to approach 100 zetabytes within the next five years so I am curious how we will end up storing all of that and the kinds of technologies involved!