For the storage market, judgment day will come some time in 2017. That’s when sales of solid state storage devices will exceed conventional spinning hard drive sales—at least according to a report in The Register that is based on Gartner data and estimates provided by investment firm Stifel.
Stifel predicts that conventional hard disk drive (HDD) sales will rise at a compound annual growth rate (CAGR) of 4 percent from $9.1bn in 2014 to $11.0 in 2017. By contrast, the firm predicts that sales of solid state storage devices (SSDs) will continue rising at a staggering CAGR of 20 percent, from $5.8bn in 2014 to $11.5bn in 2017. By 2019 solid state storage revenues are predicted to exceed HDD revenues by about a third, with growth showing no sign of slowing.
These figures are contradicted by a less bullish report from Technavio Research released in late January, predicting the solid state storage device market will grow at a CAGR of just 7 percent, reaching $10bn by 2020. That would put storage judgment day back by several years.
But whichever report you choose to believe, both agree that the demand for enterprise solid state storage devices will grow substantially over the next few years.
Since solid state storage is more expensive than conventional storage, enterprise usage has been restricted to areas where the high performance benefits justify the cost. But new technology such as 3D NAND and triple level cells (TLC) mean that the absolute price of solid state storage is falling rapidly.
3D NAND technology has already been demonstrated, and big vendors like Samsung, Toshiba/SanDisk, SK Hynix and Intel/Micron are all readying themselves to sell 32-layer or 48-layer solid stage storage devices. Samsung has already unveiled a solid state drive with a storage capacity of 16TB (although not in a standard form factor), proving that solid state drives can offer capacities that exceed the current generation of very high capacity helium-filled HDDs. Other key vendors in the solid state storage space include Seagate, SanDisk and Western Digital.
“Technological upgrades have resulted in a substantial fall of price per GB of (solid state) storage space which has increased performance and lowered the total cost of ownership,” says Navin Rajendra, Technavio’s senior researcher on the semiconductor equipment industry. “Hence, enterprise SSDs are gaining significant traction in data centers and cloud storage applications.”
And that means that means that the use of solid state storage is increasingly making economic sense in areas that were previously the domain of spinning disk media. Technavio’s report concludes that the market for solid state storage, especially in North America, is being driven by enterprise demand for higher-density storage.
Catering to this demand are new products such as Hitachi Data Systems’ (HDS) brand new A series all-flash arrays, announced in January 2016, which offer very high storage density, as well as low total cost of ownership (TCO), high energy efficiency and high performance.
Unlike previous HDS all-flash arrays, which use custom flash module drives, the A-series uses standard sized drives with multi level cell (MLC) solid state storage. (The decision to use MLC rather than TLC 3D NAND was based on a lack of supply of this newer flash, according to Bob Madaio, a Hitachi Data Systems’ senior director of product marketing.)
Particular applications that HDS is explicitly targeting with the A series arrays include virtual desktop, virtual server real-time analytics and small- to medium-sized database environments.
What’s notable about these arrays is that they all come in a 2U form factor. Inside the chassis are crammed dual IvyBridge controllers and up to 60 1.6TB standard solid state storage devices (with support for higher capacity SSDs on the roadmap for Q4 2016). There are just three configurations available, and this has been done intentionally to keep the supply chain simple and prices low, according to Madaio.
The smallest, the A220, offers 16TB of raw storage and 700,000 random read IOPS, with a street price of about $125,000. The intermediate A250 offers 48TB raw and 900,000 IOPS, while the top of the range A270 offers 96TB raw and 1,000,000 IOPS. The difference between the models comes down to the number of drives included: an A250 can for example be upgraded to an A270 with the addition of a 30-drive pack.
The company claims that the array offers an effective capacity of five times the usable capacity — up to 384TB for the A270 — using data reduction services included with the array, such as compression and deduplication. Other services include snapshots, replications, encryption (due Q2 2016) and thin provisioning. For the A270, the price per GB should work out to under $1.50 (using effective capacity once data reduction techniques have been applied).
What’s unusual about the A series compared to HDS’s other flash arrays — and some competing products — is that data deduplication and compression can be turned on or off to provide differing balances of storage efficiency and performance.
HDS’s A series will likely go head to head with all flash arrays like Pure Storage’s FlashArray//m arrays. But in terms of storage density, the A series has the edge: Pure’s //m20 comes in a 3U chassis, offering up to 40TB raw and 120+TB effective capacity. The higher end Pure //m70 offers up to 136TB raw and 400+TB effective capacity, but in a much larger (5U – 11U) physical size.
Another all solid state storage array that the A series will go up against is EMC’s XtremIO. A 1 X-Brick XtremeIO system has a usable capacity of about 16TB and an effective capacity of about 100TB, but packaged in a comparatively large 6U chassis.
Performance-wise, the //m70 offers up to 300,000 32k IOPS according to Pure’s specifications, while XtremeIO’s X-Brick system offers 150,000 IOPS, calculated as 70 percent read, 30 percent write, 8k blocks.
While solid state storage provides far higher performance than spinning disks, and the capacities of the largest individual solid state storage devices are comparable with the highest capacity spinning disks, it’s important to be clear that the price differential between solid state storage and spinning disk storage is still very large.
“I steadfastly maintain that HDD and SSD gigabyte prices are unlikely to cross for a very long time” says Jim Handy, a solid state storage expert and semiconductor analyst at Objective Analysis. “Historically, a gigabyte of NAND flash has cost between ten and twenty times as much as a gigabyte of HDD.
“Our current projections call for NAND price per gigabyte to reach 4.4 cents in 2019,” he adds. “I would expect for HDD to still be 1/10th to 1/20th of that price. Most likely 1/10th, since we expect for NAND flash to be in a significant oversupply at that time and will be selling at cost.”
He adds that if HDD prices continue to remain at around $50, then a 2019 HDD price of 0.44 – 0.22 cents per gigabyte (1/10th to 1/20th of the price of NAND flash) would imply an average HDD capacity of 11-23TB. That’s not unreasonable considering that vendors including HGST and Seagate already offer 10TB helium-filled drives.
And as long as spinning disk storage is one tenth of the cost of solid state storage, enterprise HDD usage will remain significant. Whenever revenues of SSDs do finally match revenues from HDDs, solid state storage will still only account for 10 percent of the total capacity sold.
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