International Business Machines Corporation

Si Cong Zhou

Gang Lyu

Yicheng Feng

Feng Shao

Min Fang

Jiang Yu

Shu Chen

Qing Chuan Sun

A method for recovering modified data lost from cache includes maintaining, in a cache of a primary storage system, a destage data structure indicating which modified data in the cache has been destaged. The method further maintains, in cache of a secondary storage system, a change recording data structure indicating which modified data has been replicated from the primary storage system to the secondary storage system. The method further merges the destage data structure with the change recording data structure to yield an updated change recording data structure. In the event modified data in the cache of the primary storage system is lost, the method utilizes the updated change recording data structure to determine which modified data in the secondary storage system is needed to restore the modified data lost from cache at the primary storage system. A corresponding system and computer program product are also disclosed.

Restoring data lost from battery-backed cache

This disclosure relates to a method, a system and a computer program product for tracking heat values. The method includes monitoring a first number of access operations to first data in each of a plurality of first source storage units during a cycle. The method further includes, for each of the plurality of first source storage units, calculating a first heat value based on the first number of access operations. Additionally, the method includes, in response to source data being moved from one of the first source storage units to a first target storage unit during the cycle, decreasing a calculated heat value of the one first source storage unit by a first value and increasing a calculated heat value of the first target storage unit by the first value.

Heat value tracking

A computer receives, at a target node, a replication target update, wherein the replication target update comprises a write frequency of a replication target and a size of the replication target. The computer creates a replication task to perform replication based upon the replication target update. The computer calculates a priority value of the replication task wherein the priority value is based upon the write frequency of the replication target and the size of the replication target. The computer inserts the replication task into a priority queue. The computer processes the replication task.

Data replication priority management

Growing community of inventors

Shanghai, China

Si Cong Zhou