Abstract: Provided are a method, system, and article of manufacture for using virtual copies in a failover and failback environment. Updates are copied from a primary first storage at the primary site to a secondary first storage at the secondary site during system operations. A second storage is maintained at at least one of the primary and secondary sites. A failover is performed from the primary site to the secondary site after a failure at the primary site. The at least one second storage is used after recovery of the primary site to synchronize the secondary site to the primary site. Only updates made to the secondary site during the failover are copied to or from the at least one second storage in response to the recovery at the primary site.

Abstract: Provided are a method, system, and article of manufacture for using virtual copies in a failover and failback environment. Updates are copied from a primary first storage at the primary site to a secondary first storage at the secondary site during system operations. A second storage is maintained at at least one of the primary and secondary sites. A failover is performed from the primary site to the secondary site after a failure at the primary site. The at least one second storage is used after recovery of the primary site to synchronize the secondary site to the primary site. Only updates made to the secondary site during the failover are copied to or from the at least one second storage in response to the recovery at the primary site.

Abstract: Provided are a method, system, and article of manufacture for using virtual copies in a failover and failback environment. Updates are copied from a primary first storage at the primary site to a secondary first storage at the secondary site during system operations. A second storage is maintained at least one of the primary and secondary sites. A failover is performed from the primary site to the secondary site after a failure at the primary site. The at least one second storage is used after recovery of the primary site to synchronize the secondary site to the primary site. Only updates made to the secondary site during the failover are copied to or from the at least one second storage in response to the recovery at the primary site.

Abstract: Provided are techniques for copying data. A volume container copyset that includes volume containers is received. A volume container copyset that includes volume containers is received. Each of the volume containers is associated with a copyset role, and each of the volume containers includes zero or more volumes, wherein each of the volumes in a volume container has the copyset role of that volume container. Sets of volumes are associated with a replication session, wherein each of the sets of volumes has one volume from each of the volume containers. Each of the sets of volumes has volumes associated with a copyset role that is associated with the volume containers with which each volume is associated. In response to determining that one of membership of one of the volume containers and a size of a volume in one of the volume containers has been modified, one or more corresponding volume containers in the volume container copyset are automatically modified.

Abstract: A volume container system automatically relates components of a storage area network in membership association of a volume container. The volume container is an abstract entity that maps a relationship between servers and storage devices. The entity captures network access control between servers and storage subsystems such as, for example, security, access, and zoning. Policies of the volume container guide operations in a volume container. The membership associates access and security within the volume container. The volume container reduces administration required for a storage area network, improves consistency in mapping, security, and zoning, and reduces complexity in consistently replicating a logical group of volumes, making failure recovery easier.

Abstract: Provided are a method, system, and article of manufacture for using virtual copies in a failover and failback environment. Updates are copied from a primary first storage at the primary site to a secondary first storage at the secondary site during system operations. A second storage is maintained at at least one of the primary and secondary sites. A failover is performed from the primary site to the secondary site after a failure at the primary site. The at least one second storage is used after recovery of the primary site to synchronize the secondary site to the primary site. Only updates made to the secondary site during the failover are copied to or from the at least one second storage in response to the recovery at the primary site.

Abstract: Provided are a method, system, and program for mirroring data. A relationship is established between a plurality of source data units in a primary storage and a plurality of corresponding target data units in a secondary storage. An operation is initiated to perform an initial copy of all source data units in the relationship to the corresponding target data units. An update is received to a source data unit and a determination is made of whether a first write mode is indicated. The update is copied to the source data unit in the first write mode to the corresponding target data unit if the first copy write is indicated. Otherwise, the update is copied to the source data unit corresponding target data unit in a second write mode if the first write mode is not indicated.

Abstract: Disclosed is a method, system, and program for prestaging data into cache from a storage system in preparation for data transfer operations. A first processing unit communicates data transfer operations to a second processing unit that controls access to the storage system. The first processing unit determines addressable locations in the storage system of data to prestage into cache and generates a data structure capable of indicating contiguous and non-contiguous addressable locations addressable locations in the storage system including the data to prestage into the cache. The first processing unit transmits a prestage command to the second processing unit. The prestage command causes the second processing unit to prestage into cache the data at the addressable locations indicated in the data structure. The first processing unit then requests data at the addressable locations indicated in the data structure. In response, the second processing unit returns the requested data from the cache.

Abstract: Disclosed is a method, system, and article of manufacture for processing modified meta data for data recovery operations. The meta data provides information on user data maintained in a storage device. The system determines whether meta data tracks maintained in a cache were modified and indicates in a non-volatile memory that the determined meta data tracks were modified. Data recovery operations may be initiated as a result of a system failure, such as a warmstart or coldstart recovery. During such data recovery operations, the system processes the non-volatile memory and the indications of modified meta data tracks therein to rebuild lost meta data tracks in the cache.

Abstract: Disclosed is a method, system, and article of manufacture for managing meta data. The meta data provides information on data maintained in a storage device. The system receives a request for meta data from a process and determines whether the requested meta data is in cache. After determining that the requested meta data is not in cache, the system determines whether there are a sufficient number of allocatable segments in cache to stage in the meta data and allocates segments in cache to store the meta data after determining that there are enough allocatable segments in cache. The system stages the requested meta data into the allocated segments. Alternatively, after determining that the requested meta data is in cache, the system determines whether a second process has exclusive access to the meta data in cache. After determining that the second process does not have exclusive access, the system indicates to the first process that access to the meta data is permitted.

Abstract: Disclosed is a method, system, program, and data structure for a storage controller to map logical blocks to physical storage blocks. The storage controller is in communication with at least one host system that views a logical storage space. The storage controller defines the logical storage space as a sequence of logical chunks, wherein each logical chunk comprises a plurality of logical blocks in the logical storage space. The storage controller further defines a physical storage space as a sequence of physical chunks, wherein each physical chunk comprises a plurality of physical blocks in the physical storage system. The storage controller associates each logical chunk in the sequence of logical chunks defining the logical storage space with one physical chunk in the physical storage system. Further, the contiguous logical chunks are capable of being associated with non-contiguous physical chunks.

Abstract: Provided are a method, system, and program for mirroring data. A relationship is established between a plurality of source data units in a primary storage and a plurality of corresponding target data units in a secondary storage. An operation is initiated to perform an initial copy of all source data units in the relationship to the corresponding target data units. An update is received to a source data unit and a determination is made of whether a first write mode is indicated. The update is copied to the source data unit in the first write mode to the corresponding target data unit if the first copy write is indicated. Otherwise, the update is copied to the source data unit corresponding target data unit in a second write mode if the first write mode is not indicated.

Abstract: Provided is a method, system, and program for destaging data from a first computer readable medium to a second computer readable medium. A list of entries indicating data blocks in the first computer readable medium is scanned. For each entry scanned, a determination is made as to whether the data block indicated in the scanned entry satisfies a criteria. If the data block indicated in the scanned entry satisfies the criteria, then a destage operation is called to destage the data block in the scanned entry from the first computer readable medium to the second computer readable medium. If the called destage operation is not initiated, then the scanned entry is removed from the cache list. The removed scanned entry is added to one destage wait list. During one destage operation, data blocks indicated in entries in the destage wait list are destaged.

Abstract: Provided is a method, system, and program for caching updates to one target storage device in a first and second memories, wherein the target storage device is one of a plurality of storage devices. A determination is made of an allocation of available space in the second memory to the storage devices, wherein a total of the allocation of the available space to all the storage devices exceeds one hundred percent of the available space in the second memory. An update to one target storage device is received and then a determination is made as to whether adding the update to the second memory will exceed the allocation of available space for the target storage device in the second memory. One copy of the update is written to the second memory if adding the update to the second memory will not exceed the allocation of available space for the target storage device.

Abstract: Disclosed is a system, method, and program for analyzing proposed interface ports to a device. For each proposed interface port, a determination is made of a number of single points of failure for the proposed interface port in common with interface ports currently used to access the device. For each proposed interface port, a determination is made of a relative availability rating based on the number of single points of failure for each proposed interface port.

Abstract: Disclosed is a system, method, and program for analyzing proposed interface ports to a device. Failure boundary data is read from the device indicating at least one failure boundary of a proposed interface to the device and a mask is accessed from the device. The accessed mask is applied to the failure boundary data for the proposed interface and existing interfaces to determine at least one failure boundary for the proposed interface and existing interfaces. A determination is made of a number of single points of failure for the proposed interface port from the determined failure boundaries the proposed interface has in common with interface ports currently used to access the device. A further determination is made of a relative availability rating based on the number of single points of failure for each proposed interface port.

Abstract: A method and apparatus for improving write performance in a disk array, wherein unnecessary track grouping is avoided during writes, by using a full track write counter. When a write request is received, the full track write counter for tracks in a stripe of tracks associated with the write request is analyzed to determine whether the write request involves a full track write. A cache destage is subsequently executed based on the analysis. When the write to cache is a full track write, a previous track full track count is fetched from a previous track's full write counter, a full track count of the tracks associated with the write request are set to be equal to the minimum of either the stripe width or the previous track's full track count plus one.

Abstract: Disclosed is a system and method for caching data. A processor receives data from a host to modify a track in a first storage device. The processor stores a copy of the modified data in a cache and indicates in a second storage device the tracks for which there is modified data in cache. During data recovery operations, the processor processes the second storage device and data therein to determine the tracks for which there was modified data in cache. The processor then marks 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. In further embodiments, in response to detecting a partial failure within the storage system, the processor would scan the cache to determine tracks for which there is modified data stored in the cache.

Abstract: Provided is a method, system, and program for destaging data from a first computer readable medium to a second computer readable medium. A list of entries indicating data blocks in the first computer readable medium is scanned. For each entry scanned, a determination is made as to whether the data block indicated in the scanned entry satisfies a criteria. If the data block indicated in the scanned entry satisfies the criteria, then a destage operation is called to destage the data block in the scanned entry from the first computer readable medium to the second computer readable medium. If the called destage operation is not initiated, then the scanned entry is removed from the cache list. The removed scanned entry is added to one destage wait list. During one destage operation, data blocks indicated in entries in the destage wait list are destaged.

Abstract: Disclosed is a system and method for caching data. A processor receives data from a host to modify a track in a first storage device. The processor stores a copy of the modified data in a cache and indicates in a second storage device the tracks for which there is modified data in cache. During data recovery operations, the processor processes the second storage device and data therein to determine the tracks for which there was modified data in cache. The processor then marks 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. In further embodiments, in response to detecting a partial failure within the storage system, the processor would scan the cache to determine tracks for which there is modified data stored in the cache.