Data structures containing sequence and revision number metadata used in mass storage data integrity-assuring technique

摘要

A data structure contains sequence number metadata which identifies an input/output (I/O) operation such as a full stripe write on a redundant array of independent disks (RAID) mass storage system, and also contains revision number metadata which identifies a subsequent I/O operation such as a read modify write on only a fractional component of the entire user data. The sequence number and revision number metadata are used in an error detection and correction technique, along with parity metadata, to detect and correct silent errors arising from inadvertent data path and drive data corruption. An error to a portion of the stripe is detected by a difference in sequence numbers for all of the components of data. An error arising after an I/O operation is detected by a revision number which is different from the correct revision number. The errors in both cases are corrected by using the parity metadata for the entire collection of user data and the correct information from the other components of the user data and metadata, and applying this information to an error correcting algorithm. The technique may be executed in conjunction with a read I/O operation without incurring a substantial processing overhead penalty.