Abstract: Techniques for providing lifecycle handling of faults associated with a storage appliance. The techniques can include recording information or details of one or more detected faults associated with a storage appliance in a fault database, analyzing the recorded fault information/details by an analytic tool, and determining whether to perform immediate recovery or defer recovery of the detected fault(s) based at least on a recommendation of the analytic tool. In this way, taking the storage appliance offline upon occurrence of a single fault can, for the most part, be avoided. In addition, because the detection of faults is not performed within a fault domain for a filesystem handling files for a single or limited number of volume families, a deduplication domain for the files of the filesystem is not restricted to the single or limited number of volume families.

Abstract: Techniques for providing lifecycle handling of faults associated with a storage appliance. The techniques can include recording information or details of one or more detected faults associated with a storage appliance in a fault database, analyzing the recorded fault information/details by an analytic tool, and determining whether to perform immediate recovery or defer recovery of the detected fault(s) based at least on a recommendation of the analytic tool. In this way, taking the storage appliance offline upon occurrence of a single fault can, for the most part, be avoided. In addition, because the detection of faults is not performed within a fault domain for a filesystem handling files for a single or limited number of volume families, a deduplication domain for the files of the filesystem is not restricted to the single or limited number of volume families.

Abstract: Techniques for rebuilding space accounting counters in mapping layers of storage appliances. The techniques include uniquely associating top levels of a mapping layer of a storage appliance with respective storage objects. The techniques further include determining amounts of logical storage space consumed by the respective storage objects from mappings of LBAs of the respective storage objects to virtual blocks of a virtual layer of the storage appliance. The techniques further include determining amounts of physical storage space consumed by the respective storage objects from logged information pertaining to each leaf pointer of a leaf level of the mapping layer that points to a virtual block in the virtual layer, each virtual block being mapped to a physical block in a physical layer of the storage appliance. The techniques further include using multi-threading to determine amounts of logical storage space consumed by dynamically adjustable ranges of the respective storage objects.

Abstract: A method of repairing an indirect addressing structure of a file system damaged by corruption of a virtual data block (VDB) mapping data stored in corresponding physical data blocks (PDBs) includes scanning PDB descriptors to identify PDBs storing data mapped by the corrupted VDB, where each identified PDB includes a set of PDB entries each having a backward pointer identifying a corresponding VDB entry of a corresponding VDB. The identified PDBs are scanned to identify PDB entries whose backward pointers refer to VDB entries of the corrupted VDB, then a replacement VDB is created by (1) for each of the identified PDB entries, recreating a corresponding VDB entry including a forward pointer to the identified PDB entry, and (2) incorporating the recreated VDB entries into the replacement VDB. The replacement VDB is then incorporated into the indirect addressing structure in place of the corrupted VDB.

Abstract: A technique for repairing an indirect addressing structure of a file system damaged by corruption of a mid-level mapping (MID) page includes scanning selected leaf pages to identify leaf pages associated with the corrupted MID page, then recreating the MID page by recreating pointers to the identified leaf pages. The scanning includes (1) based on an association of groups of leaf pages with corresponding sets of families of storage objects, scanning the leaf pages of only those groups of leaf pages associated with the family of storage objects for the corrupted MID page. The scanning further includes (2) performing a two-pass process including first identifying all leaf pages for the logical offset range of the corrupted MID page and then pruning those identified leaf pages that are reachable via non-corrupted MID pages, yielding the leaf pages for the corrupted MID page only, usable to recreate the corrupted MID page.

Abstract: A method of repairing an indirect addressing structure of a file system damaged by corruption of a virtual data block (VDB) mapping data stored in corresponding physical data blocks (PDBs) includes scanning PDB descriptors to identify PDBs storing data mapped by the corrupted VDB, where each identified PDB includes a set of PDB entries each having a backward pointer identifying a corresponding VDB entry of a corresponding VDB. The identified PDBs are scanned to identify PDB entries whose backward pointers refer to VDB entries of the corrupted VDB, then a replacement VDB is created by (1) for each of the identified PDB entries, recreating a corresponding VDB entry including a forward pointer to the identified PDB entry, and (2) incorporating the recreated VDB entries into the replacement VDB. The replacement VDB is then incorporated into the indirect addressing structure in place of the corrupted VDB.

Abstract: A technique for repairing an indirect addressing structure of a file system damaged by corruption of a mid-level mapping (MID) page includes scanning selected leaf pages to identify leaf pages associated with the corrupted MID page, then recreating the MID page by recreating pointers to the identified leaf pages. The scanning includes (1) based on an association of groups of leaf pages with corresponding sets of families of storage objects, scanning the leaf pages of only those groups of leaf pages associated with the family of storage objects for the corrupted MID page. The scanning further includes (2) performing a two-pass process including first identifying all leaf pages for the logical offset range of the corrupted MID page and then pruning those identified leaf pages that are reachable via non-corrupted MID pages, yielding the leaf pages for the corrupted MID page only, usable to recreate the corrupted MID page.