Abstract: Provided is a method, system, and program for processing Input/Output (I/O) requests to a storage network including at least one storage device and at least two adaptors, wherein each adaptor is capable of communicating I/O requests to the at least one storage device. An error is detected in a system including a first adaptor, wherein the first adaptor is capable of communicating on the network after the error is detected. In response to detecting the error, a master switch timer is started that is less than a system timeout period if the first adaptor is the master. An error recovery procedure in the system including the first adaptor would be initiated after the system timeout period has expired. An operation is initiated to designate another adaptor in the storage network as the master if the first adaptor is the master in response to detecting an expiration of the master switch timer.

Abstract: Provided is a method, system, and program for processing Input/Output (I/O) requests to a storage network including at least one storage device and at least two adaptors, wherein each adaptor is capable of communicating I/O requests to the at least one storage device. An error is detected in a system including a first adaptor, wherein the first adaptor is capable of communicating on the network after the error is detected. In response to detecting the error, a master switch timer is started that is less than a system timeout period if the first adaptor is the master. An error recovery procedure in the system including the first adaptor would be initiated after the system timeout period has expired. An operation is initiated to designate another adaptor in the storage network as the master if the first adaptor is the master in response to detecting an expiration of the master switch timer.

Abstract: Provided is a system for processing Input/Output (I/O) requests to a storage network including at least one storage device and at least two adaptors, wherein each adaptor is capable of communicating I/O requests to the at least one storage device. An error is detected in a system including a first adaptor, wherein the first adaptor is capable of communicating on the network after the error is detected. In response to detecting the error, a master switch timer is started that is less than a system timeout period if the first adaptor is the master. An error recovery procedure in the system including the first adaptor would be initiated after the system timeout period has expired. An operation is initiated to designate another adaptor in the storage network as the master if the first adaptor is the master in response to detecting an expiration of the master switch timer.

Abstract: A system, method and article of manufacture are provided for the automatic recovery from errors encountered during an automated Licensed Internal Code (LIC) update on a storage controller. The present invention functions with a concurrent or nonconcurrent automated LIC update. The automated recovery from many error conditions is transparent to the attached host system and on-site service personnel, resulting an improvement in the LIC update process.

Abstract: Provided is a method, system, and program for processing Input/Output (I/O) requests to a storage network including at least one storage device and at least two adaptors, wherein each adaptor is capable of communicating I/O requests to the at least one storage device. An error is detected in a system including a first adaptor, wherein the first adaptor is capable of communicating on the network after the error is detected. In response to detecting the error, a master switch timer is started that is less than a system timeout period if the first adaptor is the master. An error recovery procedure in the system including the first adaptor would be initiated after the system timeout period has expired. An operation is initiated to designate another adaptor in the storage network as the master if the first adaptor is the master in response to detecting an expiration of the master switch timer.

Abstract: Provided is a method for processing Input/Output (I/O) requests to a storage network including at least one storage device and at least two adaptors, wherein each adaptor is capable of communicating I/O requests to the at least one storage device. An error is detected in a system including a first adaptor, wherein the first adaptor is capable of communicating on the network after the error is detected. In response to detecting the error, a master switch timer is started that is less than a system timeout period if the first adaptor is the master. An error recovery procedure in the system including the first adaptor would be initiated after the system timeout period has expired. An operation is initiated to designate another adaptor in the storage network as the master if the first adaptor is the master in response to detecting an expiration of the master switch timer.

Abstract: A system, method and article of manufacture are provided for the automatic recovery from errors encountered during an automated Licensed Internal Code (LIC) update on a storage controller. The present invention functions with a concurrent or nonconcurrent automated LIC update. The automated recovery from many error conditions is transparent to the attached host system and on-site service personnel, resulting in an improvement in the LIC update process.

Abstract: A system, method and article of manufacture are provided for the automatic recovery from errors encountered during an automated Licensed Internal Code (LIC) update on a storage controller. The present invention functions with a concurrent or nonconcurrent automated LIC update. The automated recovery from many error conditions is transparent to the attached host system and on-site service personnel, resulting in an improvement in the LIC update process.

Abstract: Provided is a method, system, and program for processing Input/Output (I/O) requests to a storage network including at least one storage device and at least two adaptors, wherein each adaptor is capable of communicating I/O requests to the at least one storage device. An error is detected in a system including a first adaptor, wherein the first adaptor is capable of communicating on the network after the error is detected. In response to detecting the error, a master switch timer is started that is less than a system timeout period if the first adaptor is the master. An error recovery procedure in the system including the first adaptor would be initiated after the system timeout period has expired. An operation is initiated to designate another adaptor in the storage network as the master if the first adaptor is the master in response to detecting an expiration of the master switch timer.

Abstract: Provided is a method, system, and program for processing Input/Output (I/O) requests to a storage network including at least one storage device and at least two adaptors, wherein each adaptor is capable of communicating I/O requests to the at least one storage device. An error is detected in a system including a first adaptor, wherein the first adaptor is capable of communicating on the network after the error is detected. In response to detecting the error, a master switch timer is started that is less than a system timeout period if the first adaptor is the master. An error recovery procedure in the system including the first adaptor would be initiated after the system timeout period has expired. An operation is initiated to designate another adaptor in the storage network as the master if the first adaptor is the master in response to detecting an expiration of the master switch timer.

Abstract: A system, method and article of manufacture are provided to perform an automated concurrent licensed internal code (LIC) update and an automated nonconcurrent LIC update on a storage controller. The automated concurrent LIC update is performed on a storage controller by sequentially updating each cluster while maintaining operation of the storage controller. The automated concurrent LIC update allows multiple hosts to continue to access data via the storage controller while the system is actively undergoing the LIC update. The automated nonconcurrent LIC update is performed during the time the storage controller in not operating. The automated nonconcurrent LIC update allows service personnel to perform the update in an efficient and timely manner. When the update has completed, the storage controller becomes available to process data and the system is operating at the latest LIC level.

Abstract: A dual cluster storage server maintains track control blocks (TCBs) in a data structure to describe the data stored in cache in corresponding track images or segments. Following a cluster failure and reboot, the surviving cluster uses the TCBs to rebuild data structures such as a scatter table, which is a hash table that identifies a location of a track image, and a least recently used (LRU)/most recently used (MRU) list for the track images. This allows the cache data to be recovered. The TCBs describe whether the data in the track images is modified and valid, and describe forward and backward pointers for the data in the LRU/MRU lists. A separate non-volatile memory that is updated as the track images are updated is used to verify the integrity of the TCBs.

Abstract: An improved storage controller and method for storing and recovering data are disclosed. The storage controller includes a first cluster for directing data from a host computer to a storage device and a second cluster for directing data from a host computer to a storage device. A first cache memory is connected to the first cluster and a second cache memory is connected to the second cluster. A first preserved area of memory is connected to the first cluster and a second preserved area of memory is connected to the second cluster. Data is directed to the first cache and backed up to the second preserved area in a normal operating mode. Similarly, data is directed to the second cache and backed up to the first preserved area in the normal operating mode. In the event of a power failure or comparable event, data from the first and second preserved areas are transferred to, and stored on, a first storage device.

Abstract: Provided are a method, system, and program for maintaining data in a first cache and second cache, wherein a backup cache maintains a backup copy of data in the first cache, and wherein the first cache is used to cache a first set of data in a storage system and the second cache is used to cache a second set of data in the storage system. An unavailable state of the first cache is detected. In response to detecting the unavailable state, requests to the first set of data are blocked and at least one space in the second cache is allocated for data in the backup cache. Requests to the first set of data are allowed to proceed after the at least one space is allocated in the second cache and before the data in the backup cache is copied to the at least one allocated space in the second cache. The data from the backup cache is copied to the allocated at least one space in the second cache after the requests to the first set of data are allowed to proceed.

Abstract: Provided is a method, system, and program for processing Input/Output (I/O) requests to a storage network including at least one storage device and at least two adaptors, wherein each adaptor is capable of communicating I/O requests to the at least one storage device. An error is detected in a system including a first adaptor, wherein the first adaptor is capable of communicating on the network after the error is detected. In response to detecting the error, a master switch timer is started that is less than a system timeout period if the first adaptor is the master. An error recovery procedure in the system including the first adaptor would be initiated after the system timeout period has expired. An operation is initiated to designate another adaptor in the storage network as the master if the first adaptor is the master in response to detecting an expiration of the master switch timer.

Abstract: An improved storage controller and method for storing and recovering data are disclosed. The storage controller includes a first cluster for directing data from a host computer to a storage device and a second cluster for directing data from a host computer to a storage device. A first cache memory is connected to the first cluster and a second cache memory is connected to the second cluster. A first preserved area of memory is connected to the first cluster and a second preserved area of memory is connected to the second cluster. Data is directed to the first cache and backed up to the second preserved area in a normal operating mode. Similarly, data is directed to the second cache and backed up to the first preserved area in the normal operating mode. In the event of a power failure or comparable event, data from the first and second preserved areas are transferred to, and stored on, a first storage device.

Abstract: Provided are a method, system, and program for maintaining data in a first cache and second cache, wherein a backup cache maintains a backup copy of data in the first cache, and wherein the first cache is used to cache a first set of data in a storage system and the second cache is used to cache a second set of data in the storage system. An unavailable state of the first cache is detected. In response to detecting the unavailable state, requests to the first set of data are blocked and at least one space in the second cache is allocated for data in the backup cache. Requests to the first set of data are allowed to proceed after the at least one space is allocated in the second cache and before the data in the backup cache is copied to the at least one allocated space in the second cache. The data from the backup cache is copied to the allocated at least one space in the second cache after the requests to the first set of data are allowed to proceed.

Abstract: Provided is a method, system, and program for processing Input/Output (I/O) requests to a storage network including at least one storage device and at least two adaptors, wherein each adaptor is capable of communicating I/O requests to the at least one storage device. An error is detected in a system including a first adaptor, wherein the first adaptor is capable of communicating on the network after the error is detected. In response to detecting the error, a master switch timer is started that is less than a system timeout period if the first adaptor is the master. An error recovery procedure in the system including the first adaptor would be initiated after the system timeout period has expired. An operation is initiated to designate another adaptor in the storage network as the master if the first adaptor is the master in response to detecting an expiration of the master switch timer.

Abstract: A system and method for changing the number of logical volumes in a drawer in a rack in a direct access storage device subsystem is disclosed. The method and system are able to change the number of logical volumes without disrupting access to the other logical volumes in the rack. Channel connection addresses, which are logical volume addresses as known by the CPUs, are freed by removing the old drawer and then are mused. If the new drawer has more logical volumes than the old drawer, the next unused channel connection addresses are used with the new drawer. In a subsystem having a storage controller for providing control for a plurality of direct access storage devices, the logical volumes are spread across multiple physical devices. The storage controller maintains configuration data for the entire subsystem in redundant, non-volatile storage locations reserved specifically for its use.

Abstract: A system and method for reducing device wait time in response to a host initiated write operation modifying a data block. The system includes a host computer channel connected to a storage controller which has cache memory and a nonvolatile storage buffer in a first embodiment. An identical system makes up the second embodiment with the exception that there is no nonvolatile storage buffer in the storage controller of the second embodiment. The controller in either embodiment is coupled to a cache storage drawer containing a plurality of DASD devices for implementing a RAID parity data protection scheme, and for permanently storing data. The drawer has nonvolatile cache memory which is used for accepting data destaged from controller cache. In a first embodiment, no commit reply is sent to the controller to indicate that data has been written to DASD. Instead a status information block is created to indicate that the data has been destaged from controller cache but is not committed.