Abstract: A data storage system includes a plurality of servers, a plurality of external interface providers each deployed on one of the servers, and a plurality of data storage controllers each deployed on one of the servers. Each of the providers is configured to receive a data access request, to identify one of the controllers that can satisfy the request, and to forward the request to the identified controller. The system further includes a plurality of data storage modules independent of the servers. The providers, controllers and modules are in communication with each other. Each of the controllers exclusively manages a portion of data content in at least one of the modules, and satisfies data access requests received from the providers by accessing the portion of data content in the at least one module.

Abstract: A data storage system manager includes one or more servers, at least one data collector deployed on at least one of the servers, at least one policy engine deployed on at least one of the servers, and at least one configuration manager deployed on at least one the servers. The at least one data collector is configured to collect resource utilization information including data storage wear rate of data storage system data storage modules. The at least one policy engine is configured to evaluate the collected information and to initiate changes to a configuration of the data storage system based on data storage wear rate and work load distribution policies. The at least one configuration manager is configured to implement the changes initiated by the at least one policy engine to control the data storage wear rate and a skew of the work load distribution within the data storage system.

Abstract: A data storage system includes a plurality of servers, a plurality of external interface providers each deployed on one of the servers, and a plurality of data storage controllers each deployed on one of the servers. Each of the providers is configured to receive a data access request, to identify one of the controllers that can satisfy the request, and to forward the request to the identified controller. The system further includes a plurality of data storage modules independent of the servers. The providers, controllers and modules are in communication with each other. Each of the controllers exclusively manages a portion of data content in at least one of the modules, and satisfies data access requests received from the providers by accessing the portion of data content in the at least one module.

Abstract: A data storage system manager includes one or more servers, at least one data collector deployed on at least one of the servers, at least one policy engine deployed on at least one of the servers, and at least one configuration manager deployed on at least one the servers. The at least one data collector is configured to collect resource utilization information including data storage wear rate of data storage system data storage modules. The at least one policy engine is configured to evaluate the collected information and to initiate changes to a configuration of the data storage system based on data storage wear rate and work load distribution policies. The at least one configuration manager is configured to implement the changes initiated by the at least one policy engine to control the data storage wear rate and a skew of the work load distribution within the data storage system.

Abstract: A method and apparatus are disclosed for dynamically altering accessing of storage drives based on the technological limits of the drives. Operating parameters are set for each drive based on the technological limits for accessing that drive's type of technology. The operating parameters are then monitored during accessing of each one of the storage drives. The ones of the storage drives that have exceeded the operating parameters are identified. The accessing of the identified storage drives is altered so that none of the storage drives exceeds the operating parameters.

Abstract: An apparatus and method for storing track layout information for performing update write operations is provided. In particular, the present invention provides an apparatus and method for storing track layout information based on cylinders which is then used to verify a quick write operation. A quick write operation is an update write operation in which track data need not be read from the physical storage device before performing an update of one or more records in the track. With the present invention, as tracks are written to or read from a storage device, such as a DASD or Non-Volatile Store (NVS), a cylinder table is populated with information identifying the tracks that meet criteria set for identifying tracks that are candidates for future quick write operations. The track layout information is stored on a cylinder basis.

Abstract: Each time a track is referenced, a value representing the last referenced age is entered for a track entry in a last referenced age table (LRAT). The last referenced age table is indexed by track. A second table, an age frequency table (AFT), counts all segments in use in each reference age. The AFT is indexed by the reference age of the tracks. When a track is referenced, the number of segments used for the track is added to a segment count associated with the last referenced age of the track. The segment count tallies the total number of segments in use for the reference age for all tracks referenced to that age. The number of segments used for the previous last referenced age of the track is subtracted from the segment count associated with the previous last referenced age in the AFT. When free_space is needed, tracks are discarded from the LRAT by reference age, the oldest first.

Abstract: A data processing system, computer program product, and data processing system for providing an adjustable level of synchronicity between duplicated transactions is disclosed. An acceptable level of lag between transactions is specified. Duplicated transactions performed at redundant systems are allowed to lag behind the corresponding transactions at the primary system by the specified amount of lag. Lag may be measured in terms of number of transactions, an amount of data, amount of time, or using any other suitable metric.

Abstract: A method and apparatus for transferring data from a first storage system to a second storage system in which the first storage system includes a first plurality of storage devices and the second storage system includes a second plurality of storage devices. Data is transferred using a pair of devices selected for transferring data for all of the storage devices. Data to be transferred from source storage devices within the first plurality of storage devices is placed or queued on a selected primary storage device within the first plurality of storage devices. The data is sent to a selected secondary storage device within the plurality of storage devices. The data is relocated from the selected secondary storage device to target storage devices within the second plurality of storage devices.

Abstract: A method for use in a peer to peer remote copy (PPRC) system having primary and secondary storage systems to make data available from established PPRC storage volume pairs includes isolating the secondary storage system to be in a stand alone state such that access from any storage systems and hosts is prevented. It is then determined if each storage volume of the secondary storage system is part of an established PPRC storage volume pair. Each established PPRC storage volume pair is then terminated such that the storage volumes of the secondary storage system that are part of the established PPRC storage volume pairs are accessible to hosts. The secondary storage system is then made available to hosts to effect data recovery of the established PPRC storage volumes.

Abstract: A method and apparatus in a data processing system for copying data. A request is received to copy data from a first storage system to second storage system, wherein the request identifies a source volume on the first storage system and a target volume on the second storage system and wherein data is located on a first source volume in the first storage system. Data is transferred to a second source volume in the first storage system. A pair is automatically established between the second source volume and the target volume. The data for the request is copied from the second source volume to the target volume after the pair has been automatically established. The pair is terminated after the data has been copied to the target volume. The requester originating the request is notified of the result of the copy operation.

Abstract: A method and apparatus in a data processing system for managing data access to a plurality of storage devices. The present invention may be applied to copy operations involving virtual tracking. The plurality of storage devices is grouped into a set of groups. Responsive to a request for a copy operation to copy data from a first storage device to a second storage device, a determination is then made as to whether the first storage device and the second storage device are in the same group within the plurality of groups. Responsive to the first storage device and the second storage device being in the same group, a data file pointer to the original data is stored in a data structure for the second storage device. Responsive to an absence of the first storage device and the second storage device being in the same group, occurrence of the copy operation is prevented.

Abstract: A memory system, and a method for controlling prestaging activities based upon the availability of resources within the memory system. Prestage requests are stored in a shared memory accessible to a resource controller and one or more memory controllers. When the resource controller determines that there are sufficient unused cache memory and sufficient unused memory device back-end bandwidth available to prestage at least one data track, a message is broadcast to all of the memory controllers. Those memory controllers with sufficient unused throughput accept the prestage requests and copy the associated data tracks from the memory devices to the cache memory. Counters are maintained in the shared memory to track the number of prestage requests in the process of being serviced, and the number of prestaged data tracks already buffered in cache memory and waiting to be accessed by an external host.

Abstract: A data storage system including first, second, third and fourth virtual storage volumes, the first and second virtual storage volumes controlled to enable a mirroring and synchronization of data therebetween. The data storage system further includes a first processor that is responsive to a “copy pair” command or its equivalent to copy a directory from the first virtual storage volume to a directory of the third virtual storage volume. The first processor also dispatches a copy command, or its equivalent, to copy the directory of the second virtual storage volume to the directory of the fourth storage volume. A second processor is responsive to the copy command to cause a copying of the directory of the second virtual storage volume to the directory of the fourth virtual storage volume. Thus, the third and fourth virtual storage volumes are controlled to include directories which duplicate directories of the first and second virtual storage volumes.

Abstract: A data storage system includes at least first, second and third virtual storage volumes, the second and third virtual storage volumes being remotely coupled as a PPRC pair to enable a mirroring of data therebetween. The storage system is responsive to a snapshot command from a host processor, to cause transfer of the directory of the first virtual storage volume to the second virtual storage volume. The storage system then invokes a PPRC mirroring procedure which (i) detects an unsynchronized condition between the second and third virtual storage volumes (upon transfer of the directory from the first virtual storage volume to the second virtual storage volume), and (ii) causes a transfer of data, pointed to by the transferred directory, to the third virtual storage volume, until the second and third virtual storage volumes are again in synchronism.

Abstract: A memory system, and a method for controlling prestaging activities based upon the availability of resources within the memory system. Prestage requests are stored in a shared memory accessible to a resource controller and one or more memory controllers. When the resource controller determines that there are sufficient unused cache memory and sufficient unused memory device back-end bandwidth available to prestage at least one data track, a message is broadcast to all of the memory controllers. Those memory controllers with sufficient unused throughput accept the prestage requests and copy the associated data tracks from the memory devices to the cache memory. Counters are maintained in the shared memory to track the number of prestage requests in the process of being serviced, and the number of prestaged data tracks already buffered in cache memory and waiting to be accessed by an external host.

Abstract: A method and system for the automatic data recovery for a duplex pair is provided. The preferred embodiment includes the discovery of lost data on the first subsystem. A copy of the lost data is automatically transferred from the second subsystem to the first subsystem. Then the copy of the lost data is automatically written into the first subsystem. The host processor and the operator is unaware data had been lost. The method and system of the present invention eliminates the need to terminate the job which triggered the discovery of the lost data. It also eliminates the need for any involvement of the operator in the data recovery process.

Abstract: Copies of data that are stored on tracks of a primary disk volume and a backup disk volume are synchronized by a method which reduces the amount of data that is transferred. The primary disk volume includes tracks with current data (i.e., non-empty tracks) and tracks with no current data (i.e., empty tracks). The method transfers to the backup disk volume only data from non-empty tracks on the primary disk volume and then writes the data onto tracks in the backup disk volume that correspond to the non-empty tracks of the primary disk volume. Prior to writing of the data onto the backup disk volume, it is preferred that the backup disk volume have all tracks erased so that after the write action, only the tracks with current data have data written therein. Further, at the primary disk volume, only tracks having current data are read. Accordingly, substantial savings in processing and data transfer times are achieved.

Abstract: The present data file storage management system for snapshot copy operations maintains a two level mapping table which enables the data files to be copied using the snapshot copy process and only having to update a single corresponding mapping table entry when the physical location of the data file is changed. The snapshot copy updates to the contents of the first level of the two level mapping table are stored on the backend data storage devices to provide a record of the snapshot copy operation which can be used to recover the correct contents of the mapping table. This record of the snapshot copy operations remains valid even though the physical location of a copied data file instance is subsequently changed. Furthermore, the physical storage space holding the updated portions of the first level of the two level mapping table can be managed using techniques like those used to manage the physical storage space holding data file instances.