According to one embodiment, a test result of a first disk that was removed from a storage system and tested at a remote testing facility is received. A data analysis is performed on operational statistics data associated with the first disk based on one or more predetermined data patterns, where the operational statistics data was periodically collected from the storage system during operations of the storage system. A failure category of the first disk is determined based on the data analysis by comparing the operational statistics data against the predetermined data patterns. At least one of the data patterns is adjusted for subsequent determination of failure categories in view of an analysis result of the analysis, the failure category, and the testing result received from the testing facility.