Abstract: A system and method manages lock state information in a storage system. A meta-data volume node includes a lock state database which is a comprehensive source for lock state information about data containers in the system. A plurality of data volume nodes include local lock caches, which contain information about locks. Lock state messaging between the meta-data volume node and the data volume nodes is used to assign locks and to update local lock caches. The meta-data volume node is configured to determine whether input/output requests should be allowed or denied and to instruct the data volume nodes of this input/output operation result. Lock information is also sent to the data volume nodes for storage in local lock state caches to the extent the data volume nodes have the network capacity locally.

Abstract: A method for operating a computer storage system is disclosed. One or more data storage devices are configured to store a data content of a data container. A data structure having a plurality of permitted modification times (mtimes) is generated, the mtimes to control modifying a data stored in the data container. An I/O operation is performed by the storage system in response to a selected mtime. A request for the I/O operation is received from a client, and the data structure having a plurality of permitted modification times (mtimes) is generated in response to the request. The selected mtime is transmitted to the client, and an I/O operation is requested by the client in response to the selected mtime. The I/O operation is performed as an atomic I/O operation.

Abstract: A system and method caches and distributes meta-data for one or more data containers stored on a plurality of volumes configured as a striped volume set (SVS) and served by a plurality of nodes interconnected as a cluster. The SVS comprises one meta-data volume (MDV) configured to store a canonical copy of certain meta-data, including access control lists and directories, associated with all data containers stored on the SVS, and one or more data volumes (DV) configured to store, at least, data content of those containers. In addition, for each data container stored on the SVS, one volume is designated a container attribute volume (CAV) and, as such, is configured to store (“cache”) a canonical copy of certain, rapidly-changing attribute meta-data, including time stamps and container length, associated with that container.

Abstract: A storage system architecture comprises one or more volumes distributed across a plurality of nodes interconnected as a cluster. The volumes are organized as a striped volume set (SVS) and configured to store content of data containers served by the cluster in response to multi-protocol data access requests issued by clients. Each node of the cluster includes (i) a storage server adapted to service a volume of the SVS and (ii) a multi-protocol engine adapted to redirect the data access requests to any storage server of the cluster. Notably, the content of each data container is apportioned among the volumes of the SVS to thereby improve the efficiency of storage service provided by the cluster.

Abstract: A storage system architecture comprises one or more volumes distributed across the plurality of nodes interconnected as a cluster. The volumes are organized as a striped volume set (SVS) and configured to store content of data containers served by the cluster in response to data access requests issued by clients. The content of each data container is apportioned among the volumes of the SVS to thereby improve efficiency and storage service provided by the cluster. Each data container is implemented on each of the volumes of the SVS as a sparse data container which stores data amongst sections of sparseness within the data container.

Abstract: Provided is a method and system for data allocation within a storage system architecture. One or more nodes of the storage system architecture provides access to striped data stored on a striped volume set. Each node can store a volume of the striped volume set. Further, the striped volume set is identified by a striping table. When modifying the storage system architecture, such as adding a volume to, or removing a volume from, the striped volume set, the striping table is rearranged to accurately identify the location of striped data on the striped volume set. At least one restriping process implemented on the striping table affects the volume utilization efficiency, hot-spotting behavior, and distribution efficiency of the striped volume set.

Abstract: A system and method manages lock state information in a distributed file system. A meta-data volume includes a lock state database which is a comprehensive source for lock state information about a striped volume set in the system. A plurality of data volumes includes local lock caches which contain information about locks. Lock state messaging between the meta-data volume and the data volumes is used to assign locks and to update local lock caches. The meta-data volume is configured to assigned permissive areas in the data containers accessed by clients in order to efficiently manage the lock state information.

Abstract: According to an embodiment of the invention, a block allocation testing method tests the allocation of blocks to make sure they are consistent. The method first establishes a ready volumes list, including all of the most downstream volumes in a storage pool. From the ready volumes list, an inode data list is generated. Inodes are then removed from the inode data list and processed. The block pointers in the inodes are tested one by one, and compared to the downstream pointers to determine whether the copy on write bit (CWB) is properly set. It is also determined whether there is any illegal crosslinking. Once it is determined whether the pointers of a single inode are proper, the process continues with the next inode in the list.

Abstract: A technique for accelerating the creation of a hyperclone of a virtual file system. A hyperclone inode is copied from the base inode. Each indirect and direct block referenced by the base inode is also copied and the block pointers within the base inode are set to reference the copied direct data blocks. A CTW bit is set within each copied block that alerts the file system that the reference indirect or direct block is not to be deallocated.

Abstract: A system and method efficiently guarantees data consistency to clients for one or more data containers stored on a plurality of volumes configured as a striped volume set (SVS) and served by a plurality of nodes connected as a cluster. Data consistency guarantees of data containers stored on the SVS is generally provided by delegating to data volumes (DVs) sufficient authority to autonomously service input/output (I/O) requests directed to the containers using attributes, such as timestamps, of the containers. Specifically, a DV is only allowed to service I/O requests, e.g., read and write operations, to a data container, such as a file, if it has a valid ticket book for the file. A DV requests and is granted the ticket book from a container attribute volume (CAV) on a per-file basis.

Abstract: A method and a corresponding apparatus are described, where the method includes storing, in a processing system, an information set that includes a plurality of items in hierarchical relationships, each of the items containing information. The plurality of items are grouped to form a plurality of subsets of the information set. One of the plurality of subsets is identified, for which a known memory availability limit will not be exceeded when a predetermined test is subsequently performed on the identified subset. The predetermined test is then performed on the identified subset. The identification of a subset and performing of the predetermined test may be repeated for different subsets of the information set, so that all of the subsets in the information set have been tested.

Abstract: A method and apparatus for storing compressed file data stored on a disk. The method includes an improved format for the Compressed Volume File (CVF), and more specifically, 10 an improved format for the MDFAT data structure stored within the CVF. The improved format includes using an additional byte for maintaining each entry in the MDFAT data structure which increases the number of sectors within the Sector Heap that can be addressed and accessed. The improved format further allows compressed clusters to be stored in fragments in various portions of vacant storage space located throughout the Sector Heap. The new format for the MDFAT data structure includes a bit that identifies whether each cluster is being stored in fragments. The method stores the locations of each of the fragments in a Fragment Pointer List located in the first sector of the first fragment.

Abstract: An improved storage device repair mechanism is provided. The storage device repair mechanism of the preferred embodiment searches the storage device and detects cross-linked clusters and lost directories. In response to detecting a cross-linked cluster, the repair mechanism of the preferred embodiment duplicates the cross-linked cluster and attaches the cross-linked cluster to one of the cross-linked cluster chains. In response to detecting a lost directory, the repair mechanism of the preferred embodiment attaches the lost directory to the root directory.

Abstract: A method and apparatus for defragmenting compressed file data stored on a disk. The method includes a first pass in which the FAT and MDFAT entries for each file stored on the disk are rearranged into adjacent clusters, but in which no movement of the compressed file data occurs. The method includes a second pass in which the actual compressed file data is rearranged on the disk in accordance with the FAT and MDFAT entries. A reference point is identified within the disk storage space such that no compressed file data will be stored beyond the reference point after the second pass is completed. During the rearrangement of data during the second pass, compressed file data is temporarily relocated beyond the reference point if possible. During all movements of compressed file data, the method transfers as much data as can be stored within the space to which the data is to be moved.