Decoupling data and metadata in hierarchical cache system

摘要

A coordinating node creates virtual storage from a hierarchy of local and remote cache storage resources by maintaining global logical block address (LBA) metadata maps. A size of the metadata maps at each level of the hierarchy is independent of an amount of data allocated to a respective cache store at each level.

主权项

1. A system for operating on data comprising:
a storage endpoint serving as an interface to a Level 2 (L2) cache; a coordinator node serving as an interface to a Level 3 (L3) cache, the coordinator node connected to the storage endpoint over a first network connection and also connected to cloud storage acting as a Level 4 (L4) cache over a second network connection; each of the storage endpoint, coordinator node, and cloud storage maintaining a metadata map indicating locations for data for with they are respectively responsible for storing in their respective caches; wherein a size of the metadata maps is not dependent on a size of a respective cache; and further in that the metadata map maintained at the storage endpoint is smaller than the metadata map maintained at the coordinator node, and the metadata map maintained at the coordinator node is smaller than a size of the metadata map maintained at the cloud is storage; an amount of data stored at the L2 cache is greater than an amount of data stored at the L3 cache, wherein the data stored at L3 cache is decoupled from the data stored at L2 cache; and an amount of data stored in the cloud storage is greater than an amount of data stored in the L3 cache.