Destaging pinned retryable data in cache

A computer system, comprising:

• one or more processors, one or more computer-readable memories and one or more computer-readable, tangible storage devices;
• and
• program instructions, stored on at least one of the one or more computer-readable, tangible storage devices for execution by at least one of the one or more processors via at least one of the one or more memories, to perform operations comprising:
• creating a ranks scan structure with an indicator for each rank of multiple ranks that indicates whether pinned retryable data in a cache for that rank is destageable;
• partitioning a cache directory into chunks, wherein each of the chunks includes one or more tracks from the cache;
• determining a number of tasks for a scan of the cache;
• and
• executing the number of tasks to scan the cache to destage pinned retryable data that is indicated as ready to be destaged by the ranks scan structure, wherein each of the tasks selects an unprocessed chunk of the cache directory for processing until the chunks of the cache directory have been processed.

A method, comprising:

• creating, with a processor of a computer, a ranks scan structure with an indicator for each rank of multiple ranks that indicates whether pinned retryable data in a cache for that rank is destageable;
• partitioning a cache directory into chunks, wherein each of the chunks includes one or more tracks from the cache;
• determining a number of tasks for a scan of the cache;
• and
• executing the number of tasks to scan the cache to destage pinned retryable data that is indicated as ready to be destaged by the ranks scan structure, wherein each of the tasks selects an unprocessed chunk of the cache directory for processing until the chunks of the cache directory have been processed.