Method and system for caching data in a storage system

A method for handling a partial failure in a storage system, wherein the storage system processes read/write operations directed to data tracks stored in a first storage device, comprising the steps of:

• detecting a partial failure within the storage system;
• scanning a cache to determine tracks for which there is modified data stored in the cache after detecting the partial failure;
• storing in a second storage device information indicating the tracks having modified data in cache;
• scheduling the destaging of the modified data from the cache to the first storage device;
• and
• receiving and processing read/write requests directed to the first storage device before all modified data is destaged from cache.

A system for caching data received from a host system, wherein the storage system is capable of processing read/write operations from a host system and reading and writing to a first storage device including data tracks, comprising:

• a processor;
• a cache in communication with the processor;
• a second storage device for backing-up data stored in the cache;
• control logic executed by the processor, comprising:
• (i) means for receiving data to modify a track in the first storage device;
• (ii) means for indicating in the second storage device the tracks for which there is modified data in cache;
• and
• (iii) means for processing the second storage device and data therein during data recovery operations to determine the tracks for which there was modified data in cache;
• and
• (iv) means for marking the determined tracks as failed to prevent data at the determined tracks in the first storage device from being returned in response to a read request until the failure is resolved.

A system for handling a partial failure, wherein the storage controller is capable of processing read/write operations from a host system and reading and writing to a first storage device including data tracks, comprising:

• a processor;
• a cache in communication with the processor;
• a second storage device for backing-up data stored in the cache;
• control logic executed by the processor, comprising:
• (i) means for detecting a partial failure within the storage controller;
• (ii) means for scanning the cache to determine tracks for which there is modified data stored in the cache after detecting the partial failure;
• (iii) means for storing in the second storage device information indicating tracks having modified data in cache;
• (iv) means for scheduling the destaging of the modified data from the cache to the first storage device;
• and
• (v) means for receiving and processing read/write requests directed to the first storage device before all modified data is destaged from cache.

A storage system for caching data received from a host system, wherein the storage system is capable of processing read/write operations from a host system, comprising:

• a processor;
• a cache in communication with the processor;
• a first storage device storing data tracks, wherein the processor is capable of reading and writing to data tracks in the first storage device;
• a second storage device for backing-up data stored in the cache;
• control logic executed by the processor, comprising:
• (i) means for receiving data to modify a track in the first storage device;
• (ii) means for indicating in the second storage device the tracks for which there is modified data in cache;
• and
• (iii) means for processing the second storage device and data therein during data recovery operations to determine the tracks for which there was modified data in cache;
• and
• (iv) means for marking the determined tracks as failed to prevent data at the determined tracks in the first storage device from being returned in response to a read request until the failure is resolved.

A storage system for handling a partial failure, wherein the storage controller is capable of processing read/write operations from a host system, comprising:

• a processor;
• a cache in communication with the processor;
• a first storage device storing data tracks, wherein the processor is capable of reading and writing to data tracks in the first storage device;
• a second storage device for backing-up data stored in the cache;
• control logic executed by the processor, comprising:
• (i) means for detecting a partial failure within the storage controller;
• (ii) means for scanning the cache to determine tracks for which there is modified data stored in the cache after detecting the partial failure;
• (iii) means for storing in the second storage device information indicating tracks having modified data in cache;
• (iv) means for scheduling the destaging of the modified data from the cache to the first storage device;
• and
• (v) means for receiving and processing read/write requests directed to the first storage device before all modified data is destaged from cache.

A data processing system for caching data, comprising:

• a processor;
• a host system, wherein the processor is capable of processing read/write operations from the host system;
• a cache in communication with the processor;
• a first storage device storing data tracks, wherein the processor is capable of reading and writing to data tracks in the first storage device;
• a second storage device for backing-up data stored in the cache;
• control logic executed by the processor, comprising:
• (i) means for receiving data to modify a track in the first storage device;
• (ii) means for indicating in the second storage device the tracks for which there is modified data in cache;
• and
• (iii) means for processing the second storage device and data therein during data recovery operations to determine the tracks for which there was modified data in cache;
• and
• (iv) means for marking the determined tracks as failed to prevent data at the determined tracks in the first storage device from being returned in response to a read request until the failure is resolved.

A data processing system for handling a partial failure, comprising:

• a processor;
• a host system, wherein the processor is capable of processing read/write operations from the host system;
• a cache in communication with the processor;
• a first storage device storing data tracks, wherein the processor is capable of reading and writing to data tracks in the first storage device;
• a second storage device for backing-up data stored in the cache;
• control logic executed by the processor, comprising:
• (i) means for detecting a partial failure within the storage controller;
• (ii) means for scanning the cache to determine tracks for which there is modified data stored in the cache after detecting the partial failure;
• (iii) means for storing in the second storage device information indicating tracks having modified data in cache;
• (iv) means for scheduling the destaging of the modified data from the cache to the first storage device;
• and
• (v) means for receiving and processing read/write requests directed to the first storage device before all modified data is destaged from cache.

An article of manufacture for use in programming a processor to cache data, wherein the processor is capable of receiving read/write requests from a host system to a first storage device, and wherein the processor is capable of writing data to the first storage device, a cache, and a second storage device, the article of manufacture comprising a computer usable medium including at least one computer program embedded therein that is capable of causing the processor to perform the steps of:

• receiving data to modify a track in a first storage device;
• storing a copy of the modified data in a cache;
• indicating in a second storage device tracks for which there is modified data in cache;
• processing the second storage device and data therein during data recovery operations to determine the tracks for which there was modified data in cache;
• and
• marking the determined tracks as failed to prevent data at the determined tracks in the first storage device from being returned in response to a read request until the failure is resolved.

An article of manufacture for use in programming a processor to handle a partial failure in a storage system, wherein the processor is capable of receiving read/write requests from a host system to a first storage device, and wherein the processor is capable of writing data to the first storage device, a cache, and a second storage device, the article of manufacture comprising a computer usable medium including at least one computer program embedded therein that is capable of causing the processor to perform the steps of:

• detecting a partial failure within the storage system;
• scanning a cache to determine tracks for which there is modified data stored in the cache after detecting the partial failure;
• storing in a second storage device information indicating the tracks having modified data in cache;
• scheduling the destaging of the modified data from the cache to the first storage device;
• and
• receiving and processing read/write requests directed to the first storage device before all the modified data is destaged from cache.