Flash Is Faster, but Will It Last?


The flash memory used in solid state drives is fast, flexible and starting to approach the capacities needed for enterprise environments. But is it reliable enough?


That question is dogging the technology even as organizations of all stripes prepare to add flash-based SSDs in one form or another to their storage infrastructures. Most initial deployments will be limited to peripheral or non-essential operations due to the fact that current flash technology tends to wear out much faster than tried-and-true magnetic devices.


For most of its existence, the lifespan of flash drives hasn't been a problem since it was used primarily for mobile and embedded devices that tended to get replaced relatively quickly anyway, says Mary Shacklett on Byte & Switch. But now that enterprise users are sniffing around, the industry is turning to a wide range of techniques to boost the durability of flash to the three-to-five-year average for hard disks.


Among them are wear-leveling, which tries to spread the read and writes over all portions of the flash device, and improved performance of multi-level cell (MLC) technology, which is denser than its single-level cell (SLC) counterpart but generally provides only 10,000 writes before failure, roughly one-tenth the SLC performance.


In the short term, however, it looks like SLC will be the primary data center solution. Sun Microsystems and Micron Technology recently announced a new SLC design that the companies claim offers up to 1 million write cycles. Although neither company was willing to share any details on the nature of the breakthrough, they did say devices could be available within a few months, most likely in densities up to 32 Gb and built on the 34 nm process.


Meanwhile, solid state drives aimed at the PC are gaining higher capacities and longer lifespans. IBM has begun shipping the new X25-M in 160 GB capacities on the 2.5-inch form factor and is planning to drop it down to 1.8-inch within the month. The company is expecting an MTBF of 1.2 million hours, while a SATA-based server drive, the X25-E Extreme, will offer up to 2 million hours.


Regardless of what kind of storage you deploy, however, the old bugbear of disk fragmentation will still be there to make you life miserable, according to this report on MSNBC. No matter what kind of drive you use, Windows files are still saved under the NTFS format, which is actually worse for flash storage because it fragments free space so much more rapidly. Expect that within a month, drive performance, particularly speed, will start to degrade, and could drop by as much as 80 percent unless a robust defrag system is in place.


Flash technology will most certainly benefit certain aspects of enterprise computing by virtue of its strong performance characteristics and low operating costs. But no one expects it to take over completely. The trick will be to conduct a candid assessment of data center operations to determine exactly where flash can be of the most help.