Inventors:
James L. Hafner - San Jose CA, US
Carl E. Jones - Tucson AZ, US
David R. Kahler - Tucson AZ, US
Robert A. Kubo - Tucson AZ, US
David F. Mannenbach - Tucson AZ, US
Karl A. Nielsen - Tucson AZ, US
James A. O'Conner - Ulster Park NY, US
Krishnakumar S. Rao - Fremont CA, US
Assignee:
International Business Machines Corporation - Armonk NY
International Classification:
G06F 11/00
US Classification:
714 54, 714 42, 714805, 370248
Abstract:
Method, system and computer program product are provided for detecting and correcting dropped writes in a storage system. Data and a checksum are written to a storage device, such as a RAID array. The state of the data is classified as being in a “new data, unconfirmed” state. The state of written data is periodically checked, such as with a timer. If the data is in the “new data, unconfirmed” state, it is checked for a dropped write. If a dropped write has occurred, the state of the data is changed to a “single dropped write confirmed” state and the dropped write error is preferably corrected. If no dropped write is detected, the state is changed to a “confirmed good” state. If the data was updated through a read-modified-write prior to being checked for a dropped write event, its state is changed to an “unquantifiable” state.