Abstract: A storage system having a plurality of disk controllers for accepting computer access through a SAN, and a plurality of file servers for accepting computer access through a LAN. The disk controllers and file servers are connected through a connection unit to a plurality of disk drive units in a disk pool. A disk pool management unit manages the relationships between the disk controllers and file servers and the disk drive units used by the respective disk controllers and file servers, and sends information identifying the usable disk drive units to the respective disk controllers and file servers. The disk controllers and file servers use the disk drive units based on the received usable disk information.

Abstract: Restoration of data is facilitated in the storage system by combining data snapshots made by the storage system itself with data recovered by application programs or operating system programs. This results in snapshots which can incorporate crash recovery features incorporated in application or operating system software in addition to the usual data image provided by the storage subsystem.

Abstract: A system and method for managing disk space in a thin-provisioned storage subsystem. If a number of free segments in a free segment pool at a storage subsystem is detected as below a desired minimum, one or more of the following is performed: selecting and adding logical devices (LDEVs) from an internal storage as free segments to the free segment pool, transitioning LDEVs to a virtual device (VDEV), and/or selecting and adding LDEVs from an external storage as free segments to the free segment pool. The transitioning includes identifying partially used or completely used LDEVs and transitioning these to the VDEV. Data migration may also occur by: selecting a source segment at a VDEV for migration, reading data from the source segment, writing the data to a target segment, the target segment being a free segment from the free segment pool, and assigning the target segment to the VDEV.

Abstract: A storage subsystem includes a controller having a plurality of ports and a plurality of storage devices configured store information. A lock table includes attribute information and retention information for each of a plurality of storage volumes presented to a host device. The plurality of storage volumes includes a non-virtual volume that maps to a first storage device of the storage subsystem and a virtual volume that maps to a second storage device of an associated storage subsystem. The associated subsystem is linked to the storage subsystem via a communication link. The controller is configured to receive and process a request from a host to modify an attribute of the virtual volume.

Abstract: A method for archiving data from a first disk-based storage device to a second disk-based storage device includes moving an emulated tape from a first element to a second element simulatively without actually moving data associated with the emulated tape. The data associated with the emulated tape is transmitted from the first disk-based storage device to the second disk-based storage device via a communication link. The data associated with the emulated tape is removed from the first disk-based storage device.

Abstract: An apparatus, system, and method enable access to a storage system by distinguishing SCSI Object-Based Storage Device Commands (OSD) commands from Fibre Channel (FC) SCSI commands on the same port and storage subsystem. The storage subsystem has the capability of identifying the storage protocol from a corresponding command, and processes the command accordingly for a storage device formatted for use with the respective storage protocol. This way, a storage subsystem can consolidate data from several dedicated command ports to a single physical port, while also enabling a single storage system to store and provide access to data in multiple different storage protocol formats.

Abstract: A backup method for a system including a network attached storage including a primary volume and a secondary volume, and a backup server connected to the network. The network attached storage performs a resynchronization process when a backup request is received at a time point that consistency of a file system can be guaranteed, the resynchronization process making the contents of the primary and secondary volumes coincide with each other, splits the secondary volume from the primary volume and transfers data of the secondary volume to the backup server while an online operation with the primary volume continues. The backup server stores the transferred data in a recording medium. The network attached storage performs again the resynchronization process for making the contents of the primary and secondary volumes coincide with each other, after backup completion.

Abstract: A storage system having a plurality of disk controllers for accepting computer access through a SAN, and a plurality of file servers for accepting computer access through a LAN. The disk controllers and file servers are connected through a connection unit to a plurality of disk drive units in a disk pool. A disk pool management unit manages the relationships between the disk controllers and file servers and the disk drive units used by the respective disk controllers and file servers, and sends information identifying the usable disk drive units to the respective disk controllers and file servers. The disk controllers and file servers use the disk drive units based on the received usable disk information.

Abstract: A storage subsystem includes a controller having a plurality of ports and a plurality of storage devices configured store information. A lock table includes attribute information and retention information for each of a plurality of storage volumes presented to a host device. The plurality of storage volumes includes a non-virtual volume that maps to a first storage device of the storage subsystem and a virtual volume that maps to a second storage device of an associated storage subsystem. The associated subsystem is linked to the storage subsystem via a communication link. The controller is configured to receive and process a request from a host to modify an attribute of the virtual volume.

Abstract: Data migration includes copying between normal volumes and thin provisioned volumes. Data in a normal volume can be copied to a thin provisioned volume. Alternatively, data structures can be provided to facilitate converting a normal volume into a thin provisioned volume without actual copying of data. Copying from a thin provisioned volume to a normal volume is also disclosed.

Abstract: A tiered storage system according to the present invention provides for the management of migration groups. When a migration group is defined, a reference tier position is determined and the relative tier position of each constituent logical device is determined. Movement of a migration group involves migrating data in its constituent logical devices to target logical devices. The migration group is then defined by the target devices. A virtualization system makes the transition transparent to host devices.

Abstract: Restoration of data is facilitated in the storage system by combining data snapshots made by the storage system itself with data recovered by application programs or operating system programs. This results in snapshots which can incorporate crash recovery features incorporated in application or operating system software in addition to the usual data image provided by the storage subsystem.

Abstract: A system and method for managing disk space in a thin-provisioned storage subsystem. If a number of free segments in a free segment pool at a storage subsystem is detected as below a desired minimum, one or more of the following is performed: selecting and adding logical devices (LDEVs) from an internal storage as free segments to the free segment pool, transitioning LDEVs to a virtual device (VDEV), and/or selecting and adding LDEVs from an external storage as free segments to the free segment pool. The transitioning includes identifying partially used or completely used LDEVs and transitioning these to the VDEV. Data migration may also occur by: selecting a source segment at a VDEV for migration, reading data from the source segment, writing the data to a target segment, the target segment being a free segment from the free segment pool, and assigning the target segment to the VDEV.

Abstract: Data migration includes copying between normal volumes and thin provisioned volumes. Data in a normal volume can be copied to a thin provisioned volume. Alternatively, data structures can be provided to facilitate converting a normal volume into a thin provisioned volume without actual copying of data. Copying from a thin provisioned volume to a normal volume is also disclosed.

Abstract: A tiered storage system according to the present invention provides for the management of migration groups. When a migration group is defined, a reference tier position is determined and the relative tier position of each constituent logical device is determined. Movement of a migration group involves migrating data in its constituent logical devices to target logical devices. The migration group is then defined by the target devices. A virtualization system makes the transition transparent to host devices.

Abstract: A storage subsystem includes a controller having a plurality of ports and a plurality of storage devices configured store information. A lock table includes attribute information and retention information for each of a plurality of storage volumes presented to a host device. The plurality of storage volumes includes a non-virtual volume that maps to a first storage device of the storage subsystem and a virtual volume that maps to a second storage device of an associated storage subsystem. The associated subsystem is linked to the storage subsystem via a communication link. The controller is configured to receive and process a request from a host to modify an attribute of the virtual volume.

Abstract: A system and method for managing disk space in a thin-provisioned storage subsystem. If a number of free segments in a free segment pool at a storage subsystem is detected as below a desired minimum, one or more of the following is performed: selecting and adding logical devices (LDEVs) from an internal storage as free segments to the free segment pool, transitioning LDEVs to a virtual device (VDEV), and/or selecting and adding LDEVs from an external storage as free segments to the free segment pool. The transitioning includes identifying partially used or completely used LDEVs and transitioning these to the VDEV. Data migration may also occur by: selecting a source segment at a VDEV for migration, reading data from the source segment, writing the data to a target segment, the target segment being a free segment from the free segment pool, and assigning the target segment to the VDEV.

Abstract: A system and method for managing disk space in a thin-provisioned storage subsystem. If a number of free segments in a free segment pool at a storage subsystem is detected as below a desired minimum, one or more of the following is performed: selecting and adding logical devices (LDEVs) from an internal storage as free segments to the free segment pool, transitioning LDEVs to a virtual device (VDEV), and/or selecting and adding LDEVs from an external storage as free segments to the free segment pool. The transitioning includes identifying partially used or completely used LDEVs and transitioning these to the VDEV. Data migration may also occur by: selecting a source segment at a VDEV for migration, reading data from the source segment, writing the data to a target segment, the target segment being a free segment from the free segment pool, and assigning the target segment to the VDEV.

Abstract: A method for archiving data from a first disk-based storage device to a second disk-based storage device includes moving an emulated tape from a first element to a second element simulatively without actually moving data associated with the emulated tape. The data associated with the emulated tape is transmitted from the first disk-based storage device to the second disk-based storage device via a communication link. The data associated with the emulated tape is removed from the first disk-based storage device.

Abstract: In a system having an internal storage system and an external storage system, a technique is provided for allowing the external storage system to inherit performance parameters from the internal storage system. Management tables are established in each of the two storage systems, and data pertaining to desired operational characteristics stored in the management table in the internal storage system. That information is transferred to the external storage system and used control its operations in accordance with the desired performance parameter.