Journal destage relay for online system checkpoint creation

摘要

A storage system comprising a processor in operable communication with a storage device is configured to have first, second, and third tables and first, second, and third respective metadata journals storing time-based information associated, respectively, with the first, second, and third tables. The first table maps logical addresses associated with LUNs associated with the storage device to respective hash digests computed based on data residing at respective logical addresses. The second table maps a range of hash digests to respective associated physical locations on the storage device. The third table maps disk block allocation on the storage device. An online system checkpoint is created, comprising information relating to the state of the storage system at a point in time, where the first, second, and third, metadata journals are destaged in order so as to destage information stored in the respective journal up to the point in time.