A storage set (e.g., an array of hard disk drives) may experience a failure, such as a loss of power, a software crash, or a disconnection of a storage device, while writes to the storage set are in progress. Recover from the failure may involve scanning the storage set to detect and correct inconsistencies (e.g., comparing mirrors of a data set or testing checksums). However, lacking information about the locations of pending writes to the storage set during the failure, this “cleaning” process may involve scanning the entire storage set, resulting in protracted recovery processes. Presented herein are techniques for tracking writes to the storage set by apportioning the storage set into regions of a region size (e.g., one gigabyte), and storing on the nonvolatile storage medium descriptors of “dirty” regions comprising in-progress writes. The post-failure recovery process may then be limited to the regions identified as dirty.