Facebook raised eyebrows last month with its decision to pursue optical Blu-ray discs for its cold storage. But Facebook has also suggested an even odder choice for a cold storage medium -- solid-state drives.
In a presentation at the Flash Memory Summit last August, Jason Taylor, director of infrastructure at the company, suggested that "WORM flash," or an alternative solid-state technology, could provide high-density storage and longer hardware lifespan at a reasonable cost.
One of Taylor's slides issued the following challenge to the industry: "Make the worst flash possible -- just make it dense and cheap; long writes, low endurance and lower IOPS/TB are all OK."
Lydia Chan, a Facebook spokesperson, said the company continues to explore the use of a low-power version of flash for cold storage, "with the goal of finding the most efficient and scalable technology."
Some industry analysts are dubious about Facebook's pursuit of flash for cold storage. They wonder how flash can ever be cost-effective for cold storage.
"They can do it, but it'll just be expensive," said Jim Handy, chief analyst at Objective Analysis in Los Gatos, Calif. "Right now, a gigabyte of hard disk drive (HDD) space costs about one-twentieth as much as a gigabyte of flash space. And that ratio is likely to stay there. As flash prices go down, hard-disk prices go down. So, it never really makes sense from a cost standpoint to do cold storage on flash instead of on a hard disk because a hard disk is just so much cheaper."
Greg Wong, founder and principal analyst at Forward Insights in North York, Ontario, added that in examining the full total cost of ownership, he doesn't think the potential power savings of using flash over HDDs will offset the higher purchase price of the solid-state technology.
"I think the cost they want is beyond what anybody can provide at the moment, and the problem is five years later, that target cost will be even lower," Wong said. "You're always trying to catch up with their cost targets."