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2. MLC flash storage
The signs are everywhere that MLC NAND flash will continue its upward trajectory next year and officially overtake higher-cost single-level cell (SLC) flash in enterprise systems, ushering in a new era of more affordable solid-state storage.
Manufacturers have ramped up production of MLC-based solid-state drives (SSDs), and even major storage vendors that were once hesitant to use them are joining the ranks of earlier adopters such as IBM and Hewlett-Packard (HP) Co. Framingham, Mass.-based IDC predicts that MLC-based drives will command 52% of enterprise solid-state revenue next year and climb to 60% in 2013.
Jeff Janukowicz, research director of solid-state storage at IDC, said MLC-based SSDs have reached a point where they’re better able to handle the read/write mixes that traditional IT requires, thanks to advancements in their architectures, algorithms and controllers.
Online marketplace eBay Inc. turned heads this year with its 100 TB deployment of Nimbus Data Systems Inc.’s S-class solid-state storage, which uses a more industrial-strength flash variant known as enterprise MLC (eMLC).
One of the main distinctions between the different types of flash is endurance. The consensus is that SLC wears out after approximately 100,000 erase/write cycles, eMLC at 30,000 erase/write cycles and MLC at 10,000 or less. But the differentials are becoming less important as the MLC drive and third-party controller vendors make improvements.
“These controller manufacturers have found that they can actually watch the flash’s behavior, and as long as they keep track of every single block and how it performs, they can use certain blocks well beyond the 10,000 limit and up into the hundreds of thousands of uses,” said Jim Handy, founder and chief analyst at Object Analysis in Los Gatos, Calif.
Even the erase/write differential between eMLC and MLC is starting to become less of an advantage, and eMLC doesn’t appear to be gaining the level of popularity the industry expected, according to Handy.
“eMLC costs more than MLC and it’s slower,” he said, “and since everybody is buying SSDs for speed, a slower solution is a really tough sell.”
Dan Mulkiewicz, IT director at Carlsbad, Calif.-based High Moon Studios, a division of Activision Blizzard Inc., which produces popular video games such as “World of Warcraft” and “Guitar Hero,” said even the least expensive MLC SSDs have performed impressively.
High Moon started with 10 MLC-based SSDs nearly three years ago in workstations, and soon added another 60 or 70 after application build times dropped from 30 or 40 minutes to four minutes.
“I had to come up with a cheap solution, and we took a chance, and it paid off,” Mulkiewicz said, noting that SLC flash never became a consideration.
He said the failure rate on the workstations’ MLC drives was less than 5%, and manufacturer warranties have improved from a year to three years, comparable to that of hard drives.
So, Mulkiewicz had no qualms using an MLC-based cache from GridIron Systems Inc. to address an I/O bottleneck with his VMware server farm. Mulkiewicz was impressed with the dramatic performance boost. In worst-case scenarios, programmers and artists once waited 70 minutes for the code to recompile after they submitted a change. With the MLC-based cache, the wait fell to less than 10 minutes.
“We’re not only comfortable with [MLC] now,” Mulkiewicz said, “we’re dependent on it.”
This was first published in December 2011