When IBM made the first hard disk drive (HDD) about 70 years ago, it weighed over a ton and provided just 3.75 MB of storage capacity. Despite huge gains in storage density and performance in the years since, flash memory has replaced HDDs in the consumer space in all but the lowest-end laptops and tablets. In the enterprise storage industry, however, hard disk drives continue to account for a large share of the market.
Increasingly, industry experts are predicting that will change soon, too. At the 2023 Pure//Accelerate Conference, several speakers predicted the imminent death of mechanical hard disk drives. Here’s a roundup of five reasons why the end of the HDD might be in sight.
HDD Capacity vs. Flash Capacity
When flash first began to appear in solid state drives (SSDs) 10 years ago, those drives offered storage capacities around 512 GB—significantly less than the largest 4 TB HDDs. A decade later, HDDs max out around 20 TB while SSDs are available in capacities in excess of 100 TB, though smaller, more affordable 30 TB SSDs are more common.
Pure Storage Founder and Chief Visionary Officer John Cosgrove said his company had abandoned the SSD form factor years ago and moved toward Direct Flash Modules (DFMs). The company recently released a 48 TB DFM and scheduled a 75 TB DFM for release later this year, which makes it possible to deliver 1.5 petabytes (PB) in a three rack unit (RU) array, or 30 PB in a single system.
With a 150 TB DFM due in 2024 and a 300 TB unit by 2026, Cosgrove predicts a PB flash module eventually. The roadmap for HDD capacity, on the other hand, dead-ends around 40 TB by the end of the decade.
“The storage density gap between flash and disk widens year after year,” he said.
Learn more about SSDs vs. HDDs.
HDD Failure Rates
Another problem with mechanical hard disk drives is that they fail. They are composed of moving parts, and friction and heat cause problems. Some very large data centers employ people just to change out servers or disks that stopped working.
A recent study found the annualized failure rate (AFR) of HDDs to be 1.37 percent. Compare that to a lifetime failure rate of 0.89 percent for SSDs with an estimated lifespan of around five to 10 years.
SSDs were originally conceived to align with existing HDD architecture and designed to fit into HDD slots, to be controlled by disk array controllers, and to use HDD protocols, which meant flash array vendors were at the mercy of SSD manufacturers when it came to rate of expansion, capacity, density, and price. By breaking away from that design restriction, Pure’s DFM’s failure rate is one-sixth that of SSDs due to better wear level and the use of the company’s own controllers, flash architecture, and Purity operating system.
Hard disk drives can’t compete.
Learn more about How Long an SSD Lasts.
Sustainability: HDDs vs. Flash
Originally a minor factor in IT procurement, sustainability is now a dominant one. Virgin Media O2, the United Kingdom’s biggest telecom company, considers it 25 to 30 percent of procurement decisions, up from 1 percent just a few years ago. There is no comparison between HDDs and flash drives when it comes to energy consumption.
Ajit Sharma, Business Optimization Manager for Virgin Media O2, said his company lowered its data center power usage by 96 percent when it switched from disk to flash.
UK power costs have risen by five-to-10 time over the last two years, and Virgin Media O2—which uses colocation services for most of its data centers—was seeing a steep increase in power expenditures. By adopting flash arrays, it reduced its data center footprint dramatically and made significant progress toward its goal of being carbon neutral by 2040.
“We have eliminated 48,000 tons of e-waste by ditching hard drives,” Sharma said. “By saving space, we no longer need to open new data centers as we can pack so much into existing facilities.”
It’s not just good for the company—it’s good for the environment. According to estimates, 1 to 1.5 percent of planetary energy is consumed inside data centers—and storage makes up nearly a quarter of that total, almost all from HDDs. Switching from disk to flash can make a huge dent in data center energy usage and a vast reduction in greenhouse gas emissions.
Learn more about Flash Storage vs. SSDs.
Capitalizing on Existing Assets
With Artificial Intelligence (AI) top of mind for many companies, graphics processing units (GPUs) are being deployed in record numbers. Central processing units (CPUs) are also packing more cores and processing power into less space than ever.
Applications like the Metaverse, 3D simulation, and video streaming, coupled with the salaries of data scientists and highly paid IT and AI specialists, means a colossal price tag. Existing infrastructure must keep up to gain full value from those investments, and increasingly, disk doesn’t fit the bill.
Hard disk drives are too slow. They can’t serve data quickly enough. The high end of the market served as the main entry point for flash storage adoption, which was initially conceived as being useful for a very small tier of top priority data and workloads. But now enterprises want to analyze ever-larger data repositories and are turning to flash for use cases that go well beyond only top-tier storage.
“Really expensive GPUs and expensive data scientists need the highest performance to maximize their value,” said Rob Lee, Pure Storage’s CTO. “AI is no place for cold data, silos, or disk.”
Learn more about How to Use AI for Storage Management.
Cost Parity of HDD vs. Flash
Based on media procurement and maintenance and running costs over three years, Pure’s Director of Technical Strategy Eric Burgener said flash costs about 20 cents per GB in the latest DFMs. That’s comparable to the three-year cost of higher-end enterprise hard disks, he said, when you consider effective capacity, as most HDD vendors say you should store no more than 60 to 80 percent of the total capacity of a disk.
Burgener said that cost parity estimate also takes into account that HDD systems need to be replaced every three to five years, while flash systems have expected life-cycles of up to 10 years.
While there may be some creative math in these calculations, the argument that raw disk prices per GB should not be compared with raw flash prices per GB, as their life-cycle costs are higher, is compelling.
As the two shift toward more obvious parity, flash is ready to move beyond top-tier storage and take the mid-tier storage from HDD vendors. Burgener predicts that by 2026, flash will be affordable enough to eliminate the need for disk at even the very-lowest tiers of storage.
Learn more about the Best and Fastest SSDs.
Bottom Line: The End is Nigh for HDDs
Flash NAND storage—the type used in USB flash drives, memory cards, and solid state drives—already accounts for 80 percent of the global storage capacity market. The remaining 20 percent, which largely consists of enterprise storage, is under threat. Just as compact discs replaced vinyl records and cassette tapes and DVDs replaced video tapes—only to be replaced, in turn, by streaming services—flash is likely to replace hard disk drives. As capacities increase and costs decrease, hard disk drives are an endangered species in all areas of technology.