Techniques for determining vulnerability of disks are described herein. According to one embodiment, for each of a plurality of disks representing a redundant array of independent disks (RAID), a reallocated sector count associated with the disk is obtained, the reallocated sector count representing a number of sectors that have been reallocated due to an error of a storage transaction to the disk. A failure probability of the disk given the obtained reallocated sector count is determined using a predictive model, wherein the predictive model was generated based on history operating data of a set of known disks. Thereafter, a failure probability of at least two of the disks in the RAID is determined based on the failure probability of each of the disks to determine vulnerability of the RAID.