Data storage backup with lessened cache pollution

A data storage subsystem comprising:

• primary data storage;
• cache;
• backup data storage;
• and
• at least one processor configured to perform steps of:
• identifying, in a list, portions of data stored in the primary data storage for backup to the backup data storage, where the portions of the data comprise subsets of data, and where the portions of data identified in the list are prefetched downward from the primary data storage and cached in the cache;
• backing up the prefetched portions of data identified in the list from the cache to the backup data storage;
• and
• from the list, upon backup of each portion of the prefetched portions of data identified in the list from the cache to the backup data storage, marking each backed up portion of the prefetched portions of data identified in the list for accelerated Least Recently Used (LRU) discard from the cache;
• wherein the backing up step and the marking step both comprise data blocks, and the backing up step comprises a backup access pattern, wherein the backup access pattern is generated from an exact pattern of access from a backup application, and the list is arranged in a same order of the backup access pattern such that the prefetching step prefetches, in the same order specified by the backup access pattern, data blocks of prefetched portions of data identified in the list for caching before backup to the backup storage.

A computer program product for storing data with a data storage system comprising primary data storage;

• cache;
• backup data storage;
• and at least one computer-implemented processor, the computer program product comprising a non-transitory computer-usable storage medium having computer-usable program code embodied therein, the computer-usable program code comprising instructions to cause the processor to perform steps comprising:
• identifying, in a list, portions of data stored in the primary data storage for backup to the backup data storage, where the portions of the data comprise subsets of data, and where the portions of the data identified in the list are prefetched downward from the primary storage and cached in the cache;
• and
• backing up the prefetched portions of data identified in the list from the cache to the backup data storage;
• and
• from the list, upon backup of each portion of the prefetched portions of data identified in the list from the cache to the backup data storage, marking each backed up portion of the prefetched portions of data identified in the list for accelerated Least Recently Used (LRU) discard from the cache;
• wherein the backing up step and the marking step both comprise data blocks, and the backing up step comprises a backup access pattern, wherein the backup access pattern is generated from an exact pattern of access from a backup application, and the list is arranged in a same order of the backup access pattern such that the prefetching step prefetches, in the same order specified by the backup access pattern, data blocks of prefetched portions of data identified in the list for caching before backup to the backup storage.