I'm coming across more and more criticism of RAID 5 disk protection schemes. Yes, it can protect against a single disk failure but, no, it can't protect against a double disk failure. Steve Tongish of Plasmon reckons that the current focus on RAID 6 is due to the increased use of SATA drives, with their lower-than-enterprise-class duty cycle, and the increased use of disk-to-disk backup.
There is simply more data at risk on drives that are more likely to fail. You can have repeated SATA drive failures.
EMC doesn't currently offer RAID 6-protected products. NetApp has a RAID 6 (or double parity RAID) product. NetApp's Dave Hitz has discussed why it is needed in his blog.
Nexsan also offers RAID 6 with its SATA products. HDS also offers RAID 6 with its AMS and WMS products. Tongish says Plasmon will offer RAID 6 on its RAID products.
Are we seeing here the transition of the RAID controller industry to offering RAID 6 as a standard?