Abstract: A system and method for mapping file block numbers (FBNs) to logical block addresses (LBAs) is provided. The system and method performs the mapping of FBNs to LBAs in a file system layer of a storage operating system, thereby enabling the use of clients in a storage environment that have not been modified to incorporate mapping tables. As a result, a client may send data access requests to the storage system utilizing FBNs and have the storage system perform the appropriate mapping to LBAs.

Abstract: A method for operating a computer storage system maintains a client computer interacting with the storage system, the client computer storing data on a data storage device of the computer storage system. Locating, by a client-side agent executing on the client computer that examines metadata of the client computer, one or more sets of blocks allocated and then deleted, hereinafter referred to as deleted blocks, within the computer storage system. Sending a command to the storage system, the command to identify the deleted blocks within the computer storage system. Deallocating, in response to receiving the command, the identified deleted blocks within the computer storage system.

Abstract: A system and method proxies data access commands acrossed a cluster interconnect between storage appliances and a cluster using a file-level protocol. Each storage appliance activates two ports per data access, a local port for data access requests directed to clients of the storage appliance and a proxy port for data access requests directed to the partner storage appliance. Clients utilizing multi-pathing software may send data access requests to either the local port of the storage appliance or the proxy port of the storage appliance. The system and method improves high availability, especially during a loss of connectivity due to non-storage appliance hardware failure.

Abstract: A Multi-Pathing Optimization Module (MPOM) interfaces with a client to route a data access request along a most optimal path to a storage system serving data container stored on a striped volume set (SVS). The MPOM constructs and references a Location Data Structure (LDS) containing striping rules associated with the SVS, a list of network elements (N-blades) operatively connected to the client, and a list of disk elements (D-blades) sharing a node of the storage system with the listed N-blades. The MPOM executes a Client_Locate( ) function on a per data access request basis to identify the D-blade serving the volume which will receive the request. When possible, the MPOM routes the data access request directly to the N-blade sharing a node with the identified D-blade, thereby using the most optimal path from the client to the SVS.

Abstract: A system integrates an intelligent storage switch with a flexible virtualization system to enable the intelligent storage switch to provide efficient service of file and block protocol data access requests for information stored on the system. A storage operating system executing on a storage system coupled to the switch implements the virtualization system to provide a unified view of storage to clients by logically organizing the information as named files, directories and logical unit numbers. The virtualization system may be embodied as a file system having a write allocator configured to provide a flexible block numbering policy to the storage switch that addresses volume management capabilities, such as storage virtualization.

Abstract: A technique enables creation and use of a writable, read-only snapshot of an active file system operating on a storage system, such as a multi-protocol storage appliance. The writable, read-only snapshot comprises a read-only “image” (file) residing in a snapshot and a writable virtual disk (vdisk) residing in the active file system. The writable vdisk is a “shadow” image of the snapshot file image and, as such, includes an attribute that specifies the snapshot file as a backing store.

Abstract: A file which has been changed from a data storage system is restored. If the file was changed from an active file system, a set of twin pointers is created by copying from the latest pointers in the active file system before the file system was changed. A pointer from the twin pointers is compared with a pointer from a snapshot of the active file system. If a pointer from the twin pointers points to a same data block as the pointer from the snapshot, the twin pointer is written into the active file system to restore the file to the active file system. If the pointers do not point to the same data block, a data of the block is copied to a new block in the active file system to restore data changed since the snapshot was taken.

Abstract: A system and method proxies data access commands acrossed a cluster interconnect between storage appliances and a cluster using a file-level protocol. Each storage appliance activates two ports per data access, a local port for data access requests directed to clients of the storage appliance and a proxy port for data access requests directed to the partner storage appliance. Clients utilizing multi-pathing software may send data access requests to either the local port of the storage appliance or the proxy port of the storage appliance. The system and method improves high availability, especially during a loss of connectivity due to non-storage appliance hardware failure.

Abstract: A system and method proxies data access commands across a cluster interconnect between storage appliances in a cluster. Each storage appliance activates two ports for data access, a local port for data access requests directed to clients of the storage appliance and a proxy port for data access requests directed to the partner storage appliance. Clients utilizing multi-pathing software may send data access requests to either the local port of the storage appliance or the proxy port of the storage appliance.

Abstract: A logical unit number (LUN) cloning technique separates data blocks referenced by a writable virtual disk (vdisk) from data blocks referenced only by a backing store to conserve storage resources of a storage system. The LUN cloning technique separates the writable vdisk data blocks from the backing store during periods of reduced processing activity and in a manner that does not interfere with storage service provided by the system.

Abstract: A method for restoring a file which has been deleted from a data storage system is described. A set of twin pointers is created by copying from the latest pointers in the active file system at a time of restoration. A new set of pointers is created. A pointer from the twin pointers is compared with a pointer from a snapshot of the active file system made at a time earlier than the deletion of the file. In response to a pointer from the snapshot pointing to a different data block than the pointer from the twin pointers, writing the snapshot pointer into the new set of pointers. Writing the new set of pointers into the active file system at the time of restoration to restore the file to the active file system.

Abstract: A system and method for examining content of a client computer operating system is provided. Layout information of data related to a data container stored within the client computer is retrieved, where the layout information is implemented in terms of native operating system semantic of the client computer. The layout information is transmitted to a storage system. The storage system reconstructs the layout information of the data container stored within the client computer in a shadow volume implemented in terms of native operating system semantic of the storage system.

Abstract: A method and apparatus are disclosed for restoring a virtual disk (vdisk) in a data storage system as the vdisk was at an earlier time. Pointers are maintained to point to data represented by the vdisk. The pointers are saved to persistent storage at the earlier time. The data at the earlier time is maintained on the data storage device. A pointer pointing to data represented by the vdisk at a later time is compared with the pointers saved at the earlier time. If the pointer from the later time matches the pointer saved at the earlier time, keeping the pointer from the later time in the active file system. If the pointer from the later time does not match the pointers saved at the earlier time, copying a set of pointers associated with the pointer saved at the earlier time to the active file system.

Abstract: A technique enables application data stored on storage devices of a storage system to be accessible by a client as either a file or logical unit number (lun). The storage system is illustratively embodied as a multi-protocol storage appliance having a storage operating system that implements a file system. The file system logically organizes the application data as a virtual disk (vdisk) comprising a plurality of inodes including a prefix stream inode, a lun inode (storing the application data) and a suffix stream inode. The prefix and suffix stream inodes allow the vdisk to be shared over a block-based protocol or a file-based protocol by enabling apportionment of client operating system dependent storage device contents from application data contents of the vdisk.

Abstract: A system and method enabling transparent access to blocks, such as virtual disks, stored on a storage system using a file-based protocol. The system and method traps in-coming file-based protocol open commands to check for a predetermined modification to the file name. If the system and method detects the predetermined modification, then the virtual disk associated with the file name is exported to the client issuing the open command and the client receives a response from the storage system. The client, in response to receiving the response to the open command, creates a new device instantiation for reading and writing raw data to the virtual disk.

Abstract: A multi-protocol storage appliance serves file and block protocol access to information stored on storage devices in an integrated manner for both network attached storage (NAS) and storage area network (SAN) deployments. A storage operating system of the appliance implements a file system that cooperates with novel virtualization modules to provide a virtualization system that “virtualizes” the storage space provided by the devices. Notably, the file system provides volume management capabilities for use in block-based access to the information stored on the devices. The virtualization system allows the file system to logically organize the information as named file, directory and virtual disk (vdisk) storage objects to thereby provide an integrated NAS and SAN appliance approach to storage by enabling file-based access to the files and directories, while further enabling block-based access to the vdisks.

Abstract: A system integrates an intelligent storage switch with a flexible virtualization system to enable the intelligent storage switch to provide efficient service of file and block protocol data access requests for information stored on the system. A storage operating system executing on a storage system coupled to the switch implements the virtualization system to provide a unified view of storage to clients by logically organizing the information as named files, directories and logical unit numbers. The virtualization system may be embodied as a file system having a write allocator configured to provide a flexible block numbering policy to the storage switch that addresses volume management capabilities, such as storage virtualization.

Abstract: A method and apparatus are disclosed for restoring a virtual disk (vdisk) in a data storage system as the vdisk was at an earlier time. Pointers are maintained to point to data represented by the vdisk. The pointers are saved to persistent storage at the earlier time. The data at the earlier time is maintained on the data storage device. A pointer pointing to data represented by the vdisk at a later time is compared with the pointers saved at the earlier time. If the pointer from the later time matches the pointer saved at the earlier time, keeping the pointer from the later time in the active file system. If the pointer from the later time does not match the pointers saved at the earlier time, copying a set of pointers associated with the pointer saved at the earlier time to the active file system.

Abstract: A system integrates an intelligent storage switch with a flexible virtualization system to enable efficient service of file and block protocol data access requests for information stored on the system. A storage operating system executing on a storage system coupled to the switch implements the virtualization system to provide a unified view of storage to clients by logically organizing the information as named files, directories and logical unit numbers. The virtualization system is illustratively embodied as a file system having a write allocator configured to provide a flexible block numbering policy that addresses volume management capabilities, such as storage virtualization, at a finer granularity (e.g., a single block) than that of previous non-flexible storage virtualization schemes.

Abstract: A method for restoring a virtual disk (vdisk) in an active file system to an earlier time is described. Pointers pointing to data represented by the virtual disk are maintained. The pointers are saved to persistent storage at the earlier time. A pointer at a later time is compared with the pointers saved at the earlier time. If the pointer from the later time matches the pointer saved at the earlier time, the pointer from the later time is kept in the active file system. If the pointer from the later time does not match the pointers saved at the earlier time, a set of pointers associated with the pointer saved at the earlier time is copied to the active file system.