Serial Advanced Technology Attachment (SATA) disk drives have worked their way through a range of performance and reliability problems to become a major feature in data storage systems. Aside from their rapid data transfer rate, they make it possible for companies to increase their storage capacity (into the terabyte range) without too much damage to their IT budgets. But according to Jerome Wendt, SATA disk drives haven’t ironed out all the kinks in their system just yet. In an article for Computer World, he says that SATA disk drives have a known deficiency that makes it necessary for companies to be careful when deploying the drives into a range of systems.
The problem is not that serious for small systems, but once a system goes beyond the 10TB mark it risks pieces of data becoming unreadable. Systems with over 100TB are certain to encounter this problem. The crux of the matter lies in a pesky bit error rate that occurs roughly once every 100 trillion bits. According to Wendt, not even RAID technology, which normally protects all storage systems against data loss, can detect unreadable bits on a SATA drive.
Wendt says that the problem is not really all that serious, provided companies don’t de-duplicate their data to increase their storage capacity. Even super-organised companies generate vast amounts of duplicate data as files and reports are sent around, recreated, edited, amended, saved and resaved in different locations. De-duplication gets rid of unnecessary duplicates, opens space and helps improve the organisation and management of data. The problem with the bit error rate in SATA drives, however, means that if the system can’t read a particular bit of information, and there are no duplicates to fall back on, companies risk a snowball effect. One unreadable bit of data can cause many other files to also become unreadable; the key to unlocking or reconstructing the data lies in that one vital bit that the SATA drive missed.
So while high-capacity SATA disk drives and storage systems have overcome numerous hurdles since their inception, and while they are valuable in solving the archiving and backup problems that many companies face, they are still not as infallible as users and vendors would like them to be.