Flash storage hype vs. reality

What a week for flash storage fans. IBM snapped up flash memory maker Texas Memory SystemsSkyera emerged from stealth mode with a jaw-dropping $3 per GB all-flash array and Pure Storage, another flash storage startup, recently landed $40 million in funding. All this news comes in advance of the Flash Memory Summit in Santa Clara, CA next week. So what’s behind the flash splash?

Until recently flash storage was a niche market. It was targeted primarily at applications where consistency and low latency are a requirement, such as databases, virtual desktops, gaming sites and financial trading systems. But with falling prices and improved reliability it’s starting to make inroads into the enterprise, and that’s where the big bucks are in storage. According to Gartner, the flash market in enterprise storage is expected to be worth $4 billion by 2015.

But before you relegate tried and true hard disk drives to the technology graveyard, consider the quirks of solid-state drives (SSDs). For one, flash memory has a finite write lifetime, so SSDs eventually wear out. Typically, SLC flash lasts for approximately 100,000 write cycles; MLC flash is an order of magnitude worse at around 10,000 cycles for individual data cells. Beyond those points, storing and retrieving data becomes unreliable. Flash manufacturers use a number of techniques to extend life, including error correction codes, wear leveling, bad block re- mapping and over provisioning. But none of these workarounds prolongs the life of SSDs to the reliability of their spinning disk counterparts. So it’s important to understand the wear and tear issues with flash storage before deploying it.

For a heads-up on how others are using SSDs, the enterprise applications track at the Flash Storage Summit has some interesting speakers discussing the use of flash drives in the healthcare and media sectors. My two cents: flash storage will become another storage tier in the enterprise for apps that need blazingly fast response times, but for everything else, the price of disk continues to drop way faster than flash storage is dropping and will not replace primary disk storage any time soon.

Question of the week

Will SSDs replace disk, as disk replaced tape?