CACHE EVICTION OF INACTIVE BLOCKS USING HEAT SIGNATURE

摘要

Methods and systems are presented for evicting or copying-forward blocks in a storage system during garbage collection. In one method, a block status is maintained in a first memory to identify if the block is active or inactive, blocks being stored in segments that are configured to be cacheable in a second memory, a read-cache memory. Whenever an operation on a block is detected making the block inactive in one volume, the system determines if the block is still active in any volume, the block being cached in a first segment in the second memory. When the system detects that the first segment is being evicted from the second memory, the system re-caches the block into a second segment in the second memory if the block status of the block is active and the frequency of access to the block is above a predetermined value.

主权项

1. A method comprising:
maintaining, in a first memory of a storage system, a block status for each of a plurality of blocks, the block status identifying if the corresponding block is active in any volume of the storage system, each block being associated with one or more volumes and each block being stored within one segment of a plurality of segments, wherein the plurality of segments is configured to be cacheable in a second memory that is a read cache memory; whenever an operation on a block is detected that makes the block inactive in at least one volume, determining if the block is active in any volume, the block being cached within a first segment in the second memory; when the block is not active in any volume, setting the block status of the block as inactive; detecting that the first segment is being evicted from the second memory; and re-caching, in response to the eviction of the first segment, the block into a second segment in the second memory when the block status of the block is active and a frequency of access to the block is above a predetermined value.