Patent attributes
A technique for managing RAID storage in a data storage system provides a mapping subsystem and a RAID subsystem and employs the mapping subsystem to direct repair operations on damaged RAID stripes. The mapping subsystem stores metadata that provides information about data stored in the RAID subsystem and locations of that data on RAID stripes. In response to detection of a damaged RAID stripe, the mapping subsystem selectively determines, based on the metadata, whether to perform repair operations or to avoid repair operations. As many repair operations can safely be avoided, the disclosed technique has the effect of reducing unnecessary processing in the data storage system. When the RAID subsystem includes flash drives, the technique also reduces write amplification, thus preserving flash drives which might otherwise be subject to premature wear.
