Opinion

posted on 11 July 2008 15:38

Xyratex’ CTO, Malcolm Muggeridge, sent this comment in response to the RAID Inc. and NEC Corporation of America point about only the D-Series RAID controller detecting and preventing silent read failures on SATA drives:

"All drives qualified and shipped with Xyratex storage systems have ECC protection on the media and in the electronics data path. SAS drives have stronger protection than SATA drives – which is why Xyratex recommends SAS drives for mission critical applications. Xyratex RAID also has a background verify function which proactively does reads to verify that there have been no media errors. Xyratex does extensive design reviews and design qualification with all drives that ship with the storage systems. Additionally, a system level test is executed on all systems prior to production shipment."

"Xyratex has a long history of improving the reliability of storage devices and systems. Even greater minimization of disc failure is achieved through Xyratex’s multi-decade technical expertise in the development of storage systems. The result is a reliability experience three times greater than non-Xyratex SATA-based storage. Xyratex shipped 14% of worldwide external storage capacity in 2007 and 75% of world’s 3.5” drives were produced using Xyratex equipment. As widely deployed as Xyratex is, we are not aware of any customers experiencing the errors referenced in the article."

There is no independent and authoritative third-party recognition that there is a problem. RAID Inc. has received input from some HPC and government customers, who are unidentified for reasons of commercial confidentiality, that they have encountered silent drive errors on SATA drives. We don't know which brand and type of SATA drives and nor do we know which drive array subsystems they were in and which controllers were used.

Infortrend similarly refutes the notion of a general problem, mentioning that PVR-class (personal video recorder) SATA drives can skimp on error checking but not others and certainly not its controllers.

^{[Chris Mellor.]}