摘要:
Accessing stored data includes providing a virtual storage area having a table of pointers that point to sections of at least two other storage areas, where the virtual storage area contains no sections of data, in response to a request for accessing data of the virtual storage area, determining which particular one of the other storage areas contain the data, and accessing the data on the particular one of the other storage areas using the table of pointers. Accessing stored data may also include associating a first one of the other storage areas with the virtual storage area, where the virtual area device represents a copy of data of the first one of the other storage areas. Accessing stored data may also include causing all of the pointers of the table to initially point to sections of the first one of the other storage areas when the virtual storage area is initially associated with the first one of the other storage areas. The storage areas may be storage devices. The sections may be tracks.
摘要:
Restoring data includes providing data in a first storage area that contains sections of data, providing data in a second storage area where the second type has, for each section of data thereof, at least one of: a pointer to a corresponding section of data of the first storage area and a pointer to corresponding section of data of a third storage area of the first type. In one embodiment, a sections of the first storage area are replaced with pointers to the third storage area. In other embodiments, sections of a fourth storage area of the first type are replaced with pointers to the third storage area and optionally with pointers to the first storage area. In another embodiment, data is copied from the second storage area to a third storage area of the second type.
摘要:
A method and apparatus for enabling an on-line reconfiguration of striped data in a disk array storage device. A replicated copy of the striped logical device is made in parallel with host operations. A logical device with a new configuration is then substituted for access by the host application even before any data is transferred to locations within the newly configured logical device. Independent processes operating in this disk array storage device reconfigure the data transparently to any host operations while accommodating host I/O requests directed to locations in the new configuration.
摘要:
A method for enabling a data processing system with a host running under an operating system and with a disk array storage device organized by logical devices to processes plural I/O requests from one or more host processors concurrently.
摘要:
A method for copying data from a source disk storage device to a destination disk storage device. In response to a copy command from a requesting host application identifying the storage locations in source and destination disk storage devices, an environment is established. Thereafter a calling system receives an immediate response that the copy operation is complete even though no data has been copied. Application programs may access storage locations in either the source or the destination disk storage device during the copy phase. A copy program transfers the date on a track-by-track basis to the storage locations in the destination disk storage device. Procedures assure that any data access to a particular track in either the source or destination disk storage devices by any application prior to the transfer of that track are accommodated to maintain data integrity.
摘要:
A method for copying a data file from a source device to a destination device. In response to a copy command from a requesting host application identifying the source file and the storage locations in a destination, an extents track is formed to establish an environment in which the file will be copied. The calling system receives an immediate response that the copy operation is complete even though no data has been copied. Application programs may access the file in either the source or the destination. A copy program transfers the file on a track-by-track basis to the destination storage locations. Procedures assure that any data access to a particular track in either the source or destination by any application prior to the transfer of that track are accommodated to maintain data integrity.
摘要:
A method for enabling for enabling overlapped input-output request to a logical device from multiple hosts with explicit allegiances. Parameters including an address range in a new input-output request are tested against corresponding address ranges in other input-output requests in a table assigned to the logical device. If a predetermined address range relationship exits, the new input-output guest transfers to an overlap polling queue.
摘要:
A method and apparatus for enabling an on-line reconfiguration of striped data in a disk array storage device. A replicated copy of the striped logical device is made in parallel with host operations. A logical device with a new configuration is then substituted for access by the host application even before any data is transferred to locations within the newly configured logical device. Independent processes operating in this disk array storage device reconfigure the data transparently to any host operations while accommodating host I/O requests directed to locations in the new configuration.
摘要:
A method and apparatus for enabling an on-line reconfiguration of striped data in a disk array storage device. A replicated copy of the striped logical device is made in parallel with host operations. A logical device with a new configuration is then substituted for access by the host application even before any data is transferred to locations within the newly configured logical device. Independent processes operating in this disk array storage device reconfigure the data transparently to any host operations while accommodating host I/O requests directed to locations in the new configuration.
摘要:
A method for enabling overlapped input/output requests to a logical device using assigned and parallel access unit control blocks. Each I/O request interrupts an operating system to assign a base and related unit control block to the input/output requests. In addition a parallel access control block is associated with each unit control block for a logical volume and a parallel access main control block is established with a logical volume through which each of the base and related unit control block can be identified. An input/output request to a logical device interrupts the operating system to assign one of the base and one of the assigned unit control blocks to the input/output requests after which control transfers back to the operating system. At a disk storage facility, the input/output request is located in a table with other input/output requests and corresponding parameters. The disk array storage facility tests the parameters for each new input/output request to determine which of a plurality of control functions will be performed.