Patent ID: 9122589
Filing Date: 2015-09-01
Classification: G06F

Abstract:
1. A data storage system, comprising: a back-end interface to physical storage including flash memory; a front-end interface to a communications network coupling the data storage system to one or more host computers; and a storage processor, the storage processor having memory including battery-backed DRAM, the storage processor being configured to execute computer program instructions to cause the data storage system to provide data storage services to the host computers using the physical storage by: eviction/destaging, the allocation operation establishing associative references in the reference structure for data blocks upon initial caching, the access operation using the reference structure to locate cached data blocks based on file references, and the eviction/destaging operation relocating cached data blocks to create room for caching other data blocks, the relocating including a first-level destaging of data blocks from the DRAM to the flash memory at a first time and a second-level destaging of data blocks from the flash memory to the physical storage at a later second time, the first-level destaging maintaining existing associative references and modifying existing page descriptors to add respective references to the flash memory.