System and program for demoting tracks from cache

A system in communication with a storage device, comprising:

• a cache;
• first and second verify lists;
• and
• circuitry coupled to the cache and enabled to:
• destage tracks from the cache to the storage device;
• add indication of destaged tracks retained in the cache to the first verify list in response to destaging the tracks;
• retain the destaged tracks in the cache;
• perform a first verification to verify that the storage device is successfully completing writing data;
• add indication of destaged tracks that are destaged after successfully completing the first verification verifying that the storage device is successfully completing the writing of data to the second verify;
• indicate destaged tracks in the first verify list eligible for removal from the cache that were destaged before the first verification in response to performing a second verification verifying that the storage device is successfully completing the writing of data;
• receive an update to a track indicated in one of the first and second verify lists;
• remove indication of the updated track from the first or second verify list;
• and
• perform the operations of destaging the tracks from the cache and retaining the destaged tracks in the cache in response to receiving the update to the track.

An article of manufacture comprising a computer readable storage medium having code that is executed to communicate with a cache and a storage device, wherein the article of manufacture is enabled to:

• destage tracks from the cache to the storage device;
• add indication of destaged tracks retained in the cache to a first verify list in response to destaging the tracks;
• retain the destaged tracks in the cache;
• perform a first verification to verify that the storage device is successfully completing writing data;
• add indication of multiple destaged tracks that are destaged during the first verification to the first verify list;
• add indication of destaged tracks that are destaged from the cache to a second verify list in response to successfully completing the first verification verifying that the storage device is successfully completing the writing of data;
• initiate a second verification of the storage device in response to completing the first verification operation;
• and
• add indication of destaged tracks destaged during the second verification to the second verify list.

An article of manufacture comprising a computer readable storage medium having code that is executed to communicate with a cache and a storage device, wherein the article of manufacture is enabled to:

• destage tracks from the cache to the storage device;
• retain the destaged tracks in the cache;
• add indication of destaged tracks retained in the cache to a first verify list in response to destaging the tracks;
• perform a first verification to verify that the storage device is successfully completing writing data;
• add indication of destaged tracks that are destaged after successfully completing the first verification verifying that the storage device is successfully completing the writing of data to a second verify list;
• indicate destaged tracks in the first verify list eligible for removal from the cache that were destaged before the first verification in response to performing a second verification verifying that the storage device is successfully completing the writing of data;
• receive an update to a track indicated in one of the first and second verify lists;
• remove indication of the updated track from the first or second verify list;
• and
• perform the operations of destaging the tracks from the cache and retaining the destaged tracks in the cache in response to receiving the update to the track.