Abstract: A method and apparatus for performing in-memory checkpoint services as a callable resource within a distributed transaction. As such, in-memory checkpoint processes can be utilized by an application as the application would use any resource available to the computer network via a distributed transaction.

Abstract: Disclosed is a method and apparatus for reading mirrored data. In one embodiment, a node receives a read request for data, identical copies of which are maintained on a primary storage device and any number of corresponding minors. A read generator coupled to the node generates a number of read operations for smaller portions of the data. Preferably, the read generator then transmits the read operations in parallel to at least two storage devices on which identical copies of the data are maintained (e.g., a primary storage device and a corresponding mirror, two mirrors of a primary storage device, etc.). The read operations may then be processed in parallel by the storage devices to which the read operations were transmitted.

Abstract: In one embodiment, a backup application is disclosed which is configured to detect that one or more incremental virtual disk files are provided in a virtual machine image. The backup application may invoke a merge function in the virtual machine monitor, and may merge the incremental virtual disk files into the base virtual disk file. Redundant data is thus eliminated, and may reduce the amount of archive media needed to store the backed-up virtual machine image.

Abstract: A system for efficient isolation of backup versions of data objects affected by malicious software includes one or more processors and a memory coupled to the processors. The memory comprises program instructions executable by the processors to implement a backup manager configured to receive an indication that a data object is infected by malicious software. In response to the indication, the backup manager is configured to identify a particular backup version of the data object to be excluded from a data set to be used for a restore operation.

Abstract: A method and mechanism for performing data backups in a computing system. A “delta” catalog is utilized for the maintenance of data backups. The delta catalog includes a backed up object table and an extent map. For a given backup, the backed up object table update stores entries which identify only those objects backed up during that backup. The backed up object table is further configured to store entries which identify objects which were deleted between the time of a prior backup procedure and a current backup procedure. The extent map is configured identify all objects present in the system at the time of a particular backup. The extent map identifies the objects which were present as one or more sequences of entries in the backed up object table.

Abstract: A system and method for generating extensible file system metadata. In one embodiment, the system may include a storage device configured to store data and a file system configured to manage access to the storage device and to store file system content. The file system may be further configured to detect a file system content access event, and in response to detecting the file system content access event, to generate a metadata record, where the metadata record is stored in an extensible, self-describing data format.

Abstract: Systems, methods, apparatus and software can provide visualization of the topology of a data protection system. Various devices making up the data protection system are displayed using graphical user interface elements such as icons. The display of the devices making up the data protection system illustrates the topology of the data protection system, connections among various system devices, device status information, device activity information, and/or device configuration information.

Abstract: Methods for utilizing a locality table when performing data deduplication are disclosed. One method involves accessing a locality table stored in memory. The locality table includes several signatures, each of which identifies one of a several data units that were consecutively added to a deduplicated data store on a persistent storage device. The method then involves searching the locality table for a new signature of a new data unit, in order to determine whether a copy of the new data unit is already present in the deduplicated data store. If the new signature is not found in the locality table, a pointer table is accessed. The pointer table indicates a subset of a set of signatures stored on the persistent storage device. In response to accessing the pointer table, the subset of the set of signatures, indicated by the pointer table, is searched for the new signature.

Abstract: Various systems and methods for monitoring an application or service group within one cluster as a resource of another cluster are disclosed. In one embodiment, a method involves detecting an error indication generated by a first cluster (e.g., the error indication can be generated by a cluster controller or service group within the first cluster). The first cluster is implemented on a cluster resource (e.g., a virtual machine) of a second cluster. In response to detecting the error indication, restart of the cluster resource is initiated.

Abstract: A method of creating backup files having less redundancy. The method creates a backup file by creating an overhead segment for each file that is to be backed up and creating a data segment containing the data that is to be backed up for each file. After creating the overhead segment and the data segment, the overhead segment is placed into an overhead stream data segment is stored in memory. The overhead segment is also positioned in the overhead stream with a pointer that identifies the data segment within the memory. For backups of subsequent servers or the same server at a later time, the backup software will create a separate overhead stream. However, a plurality of overhead streams may contain pointers to the same data segments such that redundant data segments do not need to be stored in a backup server.

Abstract: Systems and procedures may be used to coordinate the fail-back of multiple hosts in environments where the hosts share one or more data-storage resources. In one implementation, a procedure for coordinating fail-backs includes monitoring a failed data path to detect a restoration of the data path, polling remaining nodes in response to the restoration, and allowing the first node to resume communications if access has been restored to the remaining nodes.

Abstract: Auto-trespass can be at least temporarily disabled subsequent to an automatic failover. The automatic failover exchanges roles between an active path and a passive path, such that the passive path becomes the active path and vice versa. By disabling auto-trespass, hosts that are unaware that the automatic failover has occurred will not trigger another failover when those hosts attempt to perform I/O operations via the formerly-active path. This can reduce performance decreases that would otherwise occur due to the active role being traded in a “ping-pong” manner between the paths.

Abstract: A file system includes first, second, third, and fourth directories where the first and second directories are sub-directories of the third directory, the third directory is a sub-directory of the fourth directory, the first directory stores only files identified by a first file extension, the second directory stores only files identified by a second file extension, and the first and second file extensions are distinct. A method involves receiving first and second requests to open first and second files, respectively, that are contained in the file system. The first and second requests include first and second file system paths, respectively. The first file system path is modified by adding identities of the first, third, and fourth directories to the first file system path. The second file system path is modified by adding identities of the second, third, and fourth directories to the second file system path.

Abstract: A method, system, and computer readable medium for asynchronously processing write operation on a volume having copy-on-write snapshots. In one embodiment, the method comprises the steps of: updating a normal mirror with write data associated with a write operation for the volume; asynchronously copying the write data from an asynchronous mirror to at least one copy-on-write snapshot; and, once the at least one copy-on-write snapshot is updated, updating the asynchronous mirror with the write data from the normal mirror.

Abstract: An incremental backup service may be configured to backup structured files and unstructured files on a client system. A filter driver 130 may be configured to monitor write operations on the client system and log changed cluster address information for structured files. The backup service may backup changed clusters of structured files to a backup storage device. For each of the unstructured files, the backup service may compare the file size to a threshold size. If the unstructured file is smaller than the threshold size, the backup service may backup the entire unstructured file. If the file size is larger than the threshold size, the backup service may determine the ratio of changed clusters to unchanged clusters. If the ratio is below a ratio threshold, the backup service may backup the changed clusters. If the ratio is above the ratio threshold, the backup service may backup the entire file.

Abstract: A method and apparatus for backing up a storage system, e.g., one or more disk drives. In one embodiment, an apparatus utilizes a volume snapshot service (VSS) to create a snapshot image file of a computer's storage system and then subsequently reads the data blocks contained in the snapshot image file. A determination of the number of modified data blocks, i.e., the data blocks that have changed since a last backup operation, is made. The apparatus estimates a backup size from the number of modified data blocks and subsequently determines if the estimated backup size exceeds a predetermined threshold. In the event the predetermined threshold is exceeded, a backup operation is conducted.

Abstract: Applications executing on various nodes in a distributed storage environment may write data to primary storage and may also replicate the data to secondary storage via a replication target. An interval coordinator may coordinate the periodic saving of checkpoints or snapshots of the replicated data. The interval coordinator may determine the length of consistency intervals between the saving of each of the checkpoints. Writes to the replication target from each of the nodes may be associated with the current consistency interval and, in some embodiments, with a unique per-node sequence number. When transitioning between consistency intervals, each node may be configured to temporarily suspend completion of the writes and to send the replication target a consistency interval marker indicating that the node has completed all writes for the current consistency interval.

Abstract: Systems, methods, apparatus and software can utilize a markup language to import and export data that is archived using a backup and restore system. An export utility extracts data produced or processed by an application program, converts it into a markup language format, and provides it to a backup and restore system. An import utility extracts data in a markup language format, converts it to another format, and provides the data for use by the application program. In one example, the application program is a database management system.

Abstract: Data-object-level replication is performed based on storage-device-level change tracking. A method of replicating a data object (such as a file) involves accessing mapping information and change information. The mapping information identifies that one or more regions of a storage device (such as a logical volume) store portions of the data object. The change information identifies whether the regions of the storage device, which were identified by the mapping information, have been modified subsequent to a particular point in time. If the change information identifies that any of those regions of the storage device have been modified, replication of each modified one of the regions to a secondary system is initiated. Replication can be initiated from a system other than the production system.

Abstract: A plurality of routing entries may be stored in a routing table. Each routing entry may include information usable for routing a message through a network. As new routing entries are received or created, each new routing entry may be added to the routing table. However, if there is not sufficient memory or storage to add the new routing entry to the routing table, then the least recently used existing routing entry in the routing table may be replaced with the new routing entry. In the event that the replaced routing entry is needed later, the replaced routing entry may be re-created.