Patent ID: 8255630

Claim:
A storage server comprising: a processor; a mass storage device coupled to the processor; a buffer cache memory coupled to the processor to cache data read from and written to the mass storage device; a main memory storing a plurality of data block tags corresponding to blocks of data that were previously inserted into the buffer cache memory and then evicted from the buffer cache memory; an operating system stored in a memory that when executed by the processor causes the processor to: look-up a data block tag of the plurality of data block tags according to a look-up algorithm; find the data block tag; access a block of data corresponding to the data block tag in the mass storage device; and store a plurality of counters for the plurality of data block tags in a location of main memory separate from a location of the main memory storing the plurality of data block tags, wherein the operating system comprises a file system, and wherein each of the plurality of data block tags identifies a file system identification (FSID) number and a block number for the block of data corresponding to that data block tag.