Patent ID: 11663080

Abstract:
Techniques for rebuilding data in a data storage system are provided. A method includes: (a) identifying (i) a first set of degraded Ubers that contain no portions reserved for direct writing and (ii) a second set of degraded Ubers that contain at least one portion reserved for direct writing. Direct writing is a process that writes blocks to long-term storage prior to mapping those blocks in a metadata mapping structure. An Uber is a set of adjacent stripes across a respective Redundant Array of Independent Disks (RAID) array of the data storage system, and a degraded Uber is an Uber that includes at least one failed drive within its RAID array. The method further includes (b) initiating a rebuild of the first set of degraded Ubers; and (c) delaying a rebuild of each degraded Uber of the second set until all pending direct writes to blocks of that degraded Uber have been mapped by the metadata mapping structure.