Posts Tagged ‘SSD’

HDDs in Arrays are Like Fighter Jets Flying in Formation

For more than 20 years, storage system suppliers have been using software to compensate for the fact that spinning hard disk drives fail. The software, which can be embedded in a hardware device like a RAID controller or running as software on a server, is designed to recover data, when data is lost.  And given the challenges of hard disk drive designs, without some sort of protection, data will be lost.

In a hard disk drive the read/write head literally flies on a cushion of air above the surface of the platter.  The height and speed of the flight was once compared to flying a fighter jet three inches off the ground.  But when disk drives are put into a storage system, where vibration, heat, and other interference can be transferred from one disk drive to another, it’s actually more like trying to fly multiple fighter jets in formation three inches off the ground.  And all of that assumes that the storage system is in a clean, temperature-controlled environment, with conditioned power, and limited floor vibration. Using the fighter jet example and with magnetic heads flying over disk drive platters at a height of 3 microns, a single dust particle, which averages 500 microns, would appear over 40 feet high to the fighter jet, and a typical smoke particle would appear over 80 feet tall.

Now imagine you want to build a storage system that can protect the data on your disk drives, in the event that there is a fire in the data center, the building floods, smoke fills the room, the floor shakes from an earthquake or explosion, or the ceiling collapses.  Today’s spinning disk drive technology is not designed to survive these types of  physical conditions. Fortunately, flash memory and solid state disk, which are much more tolerant of a wide range of adverse conditions, have become much more affordable, and now can be applied to solve some of these complex data-protection challenges.  That is the subject of Dr. Alex Winokur’s speech entitled “Flash Forward for Reliable Data Protection and Recovery” at the upcoming Flash Memory Summit in Santa Clara, California on August 9th. We hope that you can attend.