Storage Tech: Solid State Versus Magnetic

By Charles F. Moreira

NetApp’s country manager for Malaysia and Brunei, Andy Khoo does not see traditional magnetic hard disk drives (HDD) being displaced anytime soon.

“While SSD is growing in popularity and poses the only serious threat to HDD, shipment numbers of the latter still exceed those of SSD by far, due to SSD’s cost being about six times that of HDD’s per GB, coupled with continuing concerns over its reliability compared to HDD,” said Khoo.

SSDs are currently based on flash memory technology, in which its memory cells are weakened each time data on it is erased – which is required each time data is stored on it, and while flash vendors are tackling SSD reliability issues with sophisticated wear-levelling algorithms, and manufacturing economies of scale are driving costs down, however Khoo does not believe that flash will be part of SSD’s long-term success.

Instead he believes that new technologies, such as Intel’s Phase-Change Memory, HP’s Memristor, and IBM’s Spin Torque Transfer should ultimately prove to be more viable options for SSD design than flash.

However, HDD vendors aren’t sitting still but are continuously increasing the capacities of their proven technology in innovative ways.  For example, last year, Seagate announced plans to produce a 60TB HDD based upon Heat-assisted Magnetic Recording (HAMR) technology within this decade.  HAMR is expected to be able to increase the capacity limit of magnetic recording by 100 times and in March 2012, Seagate was the first HDD maker to achieve a milestone storage density of 1TB per sq inch using HAMR technology.

“Such capacities are awfully hard for SSD vendors to keep pace, so I don’t expect to see a major cross-over occurring between HDD and SSD for about 10 years, or perhaps 15 years at the most. In the meantime, we’ll continue to see flash and SSD technologies implemented tactically, as an accelerant in hybrid storage arrays or in small capacity (purpose-built for high performance) all-flash storage arrays,” said Khoo.

“Today we see traditional HDD storage arrays transition into hybrid flash/SSD/HDD storage arrays. Within 5 years we’ll see flash being replaced by a new or better solid-state memory technology, which will enable SSDs to finally replace HDDs within 10-15 years from now,” he added.