Patent ID: 9122588
Filing Date: 2015-09-01
Classification: G06F

Abstract:
1. A method for managing data in a storage system comprising a persistent storage device and a non-volatile random access memory (NVRAM) cache device, the method comprising: establishing a direct mapping between a logical address associated with data stored on the persistent storage device and a physical address on the NVRAM device by mapping from a logical address space into a physical address space, wherein the logical address is directed to the logical address space and the physical address is directed to the physical address space, and wherein the logical address space is larger than the physical address space; performing the direct mapping from the logical address space to the physical address space by keying a hash to the logical address in the logical address space and equalizing probabilities of mapping a keyed logical address to physical addresses within the physical address space; accessing the direct mapping between the logical address associated with data stored on the persistent storage device and the physical address on the NVRAM cache device; receiving, from a host computing device coupled to the storage system, a request to access a particular unit of data stored on the persistent storage device; using the direct mapping as a basis between the logical address associated with the data stored on the persistent storage device and the physical address on the NVRAM cache device to determine whether the particular unit of data being requested is present on the NVRAM cache device; in response to determining that the particular unit of data being requested is present on the NVRAM cache device, servicing the request by accessing a copy of the particular unit of data present on the NVRAM cache device; and in response to determining that the particular unit of data being requested is not present on the NVRAM cache device, servicing the request by accessing the particular unit of data stored on the persistent storage device.