Using frequency domain to prioritize storage of metadata in a cache

摘要

A system and method for efficiently caching metadata in a storage system. Addresses from a plurality of I/O accesses to the storage system are captured and then a frequency domain representation of the addresses is generated. The frequency domain representation is used to measure the randomness of the various applications which are accessing the storage system. Scores are generated based on the measure of randomness, and scores are assigned to the various regions of the logical address space. Scores are then assigned to the metadata pages which are stored in the cache based on the region of the logical address space to which the metadata pages correspond. The scores are used when determining which metadata pages to evict from the cache. The cache will attempt to evict those metadata pages which correspond to regions of the logical address space that are servicing random I/O accesses.

主权项

1. A method comprising:
measuring an amount of randomness in a plurality of accesses to a given address space; assigning a relatively high priority to metadata associated with the given address space if the measured amount of randomness is relatively low; assigning a relatively low priority to the metadata if the measured amount of randomness is relatively high; and wherein metadata with a relatively high priority is preferentially retained in a cache over metadata with a relatively low priority.