Patent ID: 9740632
Date: 2017-08-22
CPC Classifications: G06F

Claim:
1. A method comprising: receiving a plurality of write request requests to write to an offset in a first logical device; determining, for each write request received, a second logical device that wrote to the offset, the second logical device being an ancestor of the first logical device in a hierarchical tree of snapshots; determining, for each write request received, from descendants of the second logical device in the hierarchical tree whether data in the offset of the second logical device is shadowed data or partially shadowed data; and for each write request received, removing an address-to-hash mapping for the offset of the second logical device if the data for the offset is shadowed; and moving the address-to-hash mapping to a single descendant that has sole access to the offset of the second logical device if the data for the offset is partially shadowed.