Patent ID: 11151056

Abstract:
Techniques for providing an efficient virtualization layer structure in a data storage system. The techniques include implementing multiple layers of indirection for accessing host data in the data storage system, including a mapping layer, a virtualization layer, and a physical layer. The virtualization layer includes virtual layer blocks (VLBs), each VLB including virtual pointers. Each virtual pointer is pointed to by one or more leaf pointers in the mapping layer, and points to a data block in the physical layer. The techniques include generating, for each virtual pointer in the VLB, reference count metadata to keep track of the number of leaf pointers pointing to the virtual pointer, and maintaining, in a metadata page, the reference count metadata for the virtual pointers in a three (3)-way mirror. The techniques include maintaining each VLB of the virtualization layer in a RAID stripe across multiple physical drives in the data storage system.