Storage system and methods of mapping addresses of snapshot families

摘要

There is provided a storage system capable to maintain a snapshot family comprising a plurality of members having hierarchical relations therebetween, and a method of operating thereof. The method comprises generating a mapping data structure with mapping entries each comprising mappings for mapping a logical address range associated with the mapping entry into physical address ranges respectively correlated to representative members of the snapshot family; omitting mappings corresponding to omitted member(s) different from any of the one or more representative members sharing a respective range of physical addresses; responsive to an access request directed to a certain logical address range and a certain omitted member, determining, using a predefined rule related to the hierarchical and sequential relations between members of the snapshot family, a representative member from the one or more representative members; and responding to the access request by using a physical address range correlated to the representative member.

主权项

1. A method of operating a storage system operable to manage a plurality of snapshot families, each snapshot family (SF) is constituted by SF members comprising a master logical volume and a plurality of snapshots corresponding thereto and is characterized by a SF logical address space associated with the SF, the method comprising:
generating in the storage system, for each given SF among the plurality of snapshot families, a corresponding first SF mapping data structure comprising one or more entries, wherein each entry is associated with a variable range of contiguous logical addresses within the SF logical address space and is characterized by a value that is indicative of a length of the range and its offset in the SF logical address space, and wherein each entry in the first SF mapping data structure is further associated with a second SF data structure configured to provide mapping between the range of contiguous logical addresses associated with the entry into one or more physical address ranges, respectively correlated to the SF members; upon receiving an access request specifying an addressed LUN (Logical Unit Number) and LBA (Logical Block Address) range, identifying, by the storage system, an addressed snapshot family and an addressed member therein corresponding to the addressed LUN; searching, by the storage system, a first SF mapping data structure associated with the identified addresses SF for entry associated with a range of contiguous logical addresses corresponding to LBA range specified in the access request; and searching, by the storage system, a respective second SF mapping data structure associated with the entry found in the first SF mapping data structure for identifying physical addresses corresponding to the requested LBA range in the addressed member of the addressed snapshot family.