Abstract: Provider are a method, system, and program for maintaining data in a distributed computing environment. Data is stored at a primary storage site. A data structure is processed indicating an association of data sets in the stored data, secondary storage sites, and update frequencies. In response to processing the data structure, a determination is made of one of a plurality of secondary storage sites and a determination is made of at least one data set to transmit to the determined secondary storage site at an update frequency. The determined data set is transmitted to the determined secondary storage site according to the update frequency.

Abstract: Disclosed is a method, system, program, and data structures for maintaining electronic data at a point-in-time. A first data structure indicates point-in-time data at one of a first storage location and a corresponding second storage location. A second data structure indicates point-in-time data at one of a first storage location and corresponding second storage location. A first relationship data structure indicates a relationship between the first storage location and corresponding second storage location and a second relationship data structure indicates a relationship between the first storage location and second storage location. A request to process the first storage location is processed by processing the first relationship data structure to determine the corresponding second storage location for the first storage location and processing the first data structure to determine whether data at the first storage location was transferred to the second storage location.

Abstract: Provided is a method, system, and program for releasing storage space in a first and second storage devices. Updates to the first storage device are copied to the second storage device to provide secondary storage for the updates. A first and second tables map data sets to addresses in the first and second storage devices, respectively. A first command is detected to invalidate data sets in the first table. The addresses in the first table comprise virtual addresses, and a third table provides a mapping of the virtual addresses to physical storage locations in the first storage device. A second command is generated to update the second table to invalidate the data sets in the second storage device invalidated in the first table by the first command. A third command is detected to invalidate the virtual addresses in the third table used by the data sets invalidated in the first table to free the physical storage locations in the first storage device pointed to by the invalidated virtual addresses.

Abstract: Disclosed is a method, system, program, and memory for erasing data. A request to erase data at least one storage location is received. In response, a data structure is generated indicating that each storage location subject to the erase request is in an erased state. Upon processing a request to access a storage location, a determination is made as to whether the requested storage location is indicated in the data structure. The data structure is processed to determine whether the requested storage location is in the erased state after determining that the requested storage location is indicated in the data structure. Access to the data at the requested storage location is denied after determining that the requested storage location is in the erased state.

Abstract: A multi-session data storage facility coordinates similar status changes across all sessions at appropriate times. In each session, a data mover implements data mirroring by copying updates from the primary storage to the secondary storage. A master data set, accessible by all sessions, includes a common area for posting commands and/or errors to all sessions and individual session areas for posting errors occurring in particular sessions. When a data mover receives a host initiated command, this data mover becomes a “master.” Initially, the master data mover lists the command in the master data set's common area. Whenever other, “slave” data movers notice a command in the master data set's common area, they respond by suspending their formation of consistency groups and responding with a “ready” message. The “ready” message comprises the slave data mover's consistency form time (i.e.

Abstract: A system, method, and program for maintaining data consistency among updates to data storage areas are provided. Each update has an update time the update was made. There are multiple groups of data storage areas. For each group, updates to the data storage area in the group are stored in a journal for storing updates to the group, wherein there are multiple journals. An indication is made in a memory area for each group of a group update time comprising a most recent update time of the updates in the group. The update time for each update in the group is not greater than the group update time. A determination is made of a minimum group update time across all the groups. At least one update is applied to storage if the update time for the update does not exceed the minimum group update time. The data storage areas may be partitioned among a plurality of computer systems, and may be maintained in at least one primary and secondary storage.

Abstract: Provided is a method, system, and program for releasing storage space in a first and second storage devices. Updates to the first storage device are copied to the second storage device to provide secondary storage for the updates. A first and second tables map data sets to addresses in the first and second storage devices, respectively. A first command is detected to invalidate data sets in the first table. The addresses in the first table comprise virtual addresses, and a third table provides a mapping of the virtual addresses to physical storage locations in the first storage device. A second command is generated to update the second table to invalidate the data sets in the second storage device invalidated in the first table by the first command. A third command is detected to invalidate the virtual addresses in the third table used by the data sets invalidated in the first table to free the physical storage locations in the first storage device pointed to by the invalidated virtual addresses.

Abstract: Disclosed is a method, system, program, and memory for erasing data. A table is provided indicating different groupings of system functions. Each grouping indicates at least one system function. For each grouping there is code to perform erase operations. An erase command to erase data in at least one storage location is received. A determination is then made of the grouping having system functions supported by the system and the table is processed to determine the code for the determined grouping. The code for the determined grouping is executed to perform erase operations with respect to each storage location.

Abstract: Source data is more efficiently copied to log structured target storage by pre-configuring the target storage. The invention may be practiced in a system including a host, a storage controller, and the target storage. The host maintains a directory identifying logical units of stored data, and the storage controller maintains records classifying storage space as uncollected free space, collected free space, or space-in-use. First, the host receives input including source data and specification of a logical unit for the source data. In response, the host directs the storage controller to classify any storage space of the log target storage containing data of the specified logical unit as uncollected free space. This pre-configures the log structured storage to more efficiently receive the source data.

Abstract: Disclosed is a system for managing pages in a volatile memory device for data transfer operations between a first storage area and a second storage area. The first storage area is queried to determine a number of data sets to include in a data transfer operation. A number of pages in the volatile memory device needed for the data transfer operation is then determined. A determination is then made as to whether the number of pages needed for the data transfer operation is greater than available fixed pages in a pool of pages. Available fixed pages in the pool are allocated to the data transfer operation after determining that the number of pages needed to process the data transfer operation is less than or equal to the available fixed pages in the pool.

Abstract: A method, apparatus, and article of manufacture for performing a point-in-time backup using multiple copy technologies includes steps of suspending execution of updates to the source data; determining what point-in-time backup technology is supported by the device by determining the device and extents of the source data; processing each of the extents as determined by the backup technology supported and copying the source data in point-in-time; and backing up copied entire source data to a target media. If the backup process fails, the method, apparatus, and article of manufacture provides a restart function.

Abstract: Data is stored in one or more data storage devices, the number of active data storage devices being adaptively adjusted to maximize parallelism while minimizing device overhead. Multiple datasets are first received, these being designated for storage in multiple data storage devices. Next, a first one of the received datasets is stored in a first one of the data storage devices. Concurrently with storage of the first dataset, the following steps are performed: (1) selecting a second received dataset from those remaining to be stored, (2) selecting an available data storage device by employing a predetermined criteria, and (3) beginning storage of the second dataset in the selected data storage device. The predetermined criteria for selecting an available data storage device may involve, for example, selecting an available device based on a "first fit" or a "best fit" scheme. Concurrently with storage of the second dataset, storage of a third dataset starts.

Abstract: A remote data shadowing system provides storage based, real time disaster recovery capability. Record updates at a primary site cause write I/O operations in a storage subsystem therein. The write I/O operations are time stamped and the time, sequence, and physical locations of the record updates are collected in a primary data mover. The primary data mover groups sets of the record updates and associated control information based upon a predetermined time interval, the primary data mover appending a prefix header to the record(updates thereby forming self describing record sets. The self describing record sets are transmitted to a remote secondary site wherein consistency groups are formed such that the record updates are ordered so that the record updates can be shadowed in an order consistent with the order the record updates cause write I/O operations at the primary site.