Abstract: A method, system and computer-readable medium for providing rapid failback of a computer system is described. The method, which operates during failback of a secondary computer to a primary computer, accesses a map to determine a location of a latest version of data corresponding to a read request, where the location may be within either a primary data storage or a secondary data storage. The system comprises a primary computer coupled to a primary data storage and a secondary computer coupled to a secondary data storage. The primary computer maintains a write log and the secondary computer maintains a map. The computer-readable medium contains instructions, which, when executed by a processor, performs the steps embodied by the method.

Abstract: A method, system and computer-readable medium for providing rapid failback of a computer system is described. The method, which operates during failback of a secondary computer to a primary computer, accesses a map to determine a location of a latest version of data corresponding to a read request, where the location may be within either a primary data storage or a secondary data storage. The system comprises a primary computer coupled to a primary data storage and a secondary computer coupled to a secondary data storage. The primary computer maintains a write log and the secondary computer maintains a map. The computer-readable medium contains instructions, which, when executed by a processor, performs the steps embodied by the method.

Abstract: A method, system and computer-readable medium for providing rapid failback of a computer system is described. The method, which operates during failback of a secondary computer to a primary computer, accesses a map to determine a location of a latest version of data corresponding to a read request, where the location may be within either a primary data storage or a secondary data storage. The system comprises a primary computer coupled to a primary data storage and a secondary computer coupled to a secondary data storage. The primary computer maintains a write log and the secondary computer maintains a map. The computer-readable medium contains instructions, which, when executed by a processor, performs the steps embodied by the method.

Abstract: Various methods and systems for synchronizing replicas using a single change map are disclosed. One method involves detecting a write to a first region of a volume, while synchronization of the volume with a replica volume is ongoing. If the first region is unsynchronized with respect to a corresponding region of the replica volume, replication of the write is inhibited. Otherwise, the write is replicated. Writes for which replication is inhibited will be applied to the replica volume at a later time as part of the ongoing synchronization.

Abstract: Disclosed is a method and apparatus for refreshing a copy of a data volume. In one embodiment of the method first and second data portions of a data volume are copied to first and second memory blocks, respectively, of a memory coupled to a computer system. First and second bits of a first map stored in memory are then set, wherein the first and second bits correspond to the first and second memory blocks, respectively. The first data portion of the data volume is modified after the first data portion is copied to the first memory block. A first bit in a second map stored in memory is set after data of the first data portion is modified. An instruction is generated to refresh the data contents of the first and second memory blocks. The first bit of the first map is cleared in response to generation of the refresh instruction.

Abstract: A method, system, computer-readable medium, and computer system to perform operations on selected data in a storage area. Storage locations in the storage area can be identified by a requester for performing an operation only on the data in the identified storage locations. The requester can be an application managing the data (such as a database application, file system, or user application program) or a storage manager. The storage locations containing the data are obtained by software performing the operation, which can be a storage manager or an application operating in conjunction with a storage manager, such as a storage area replication facility. The software performing the operation operates only upon the identified locations, thereby affecting only the data stored within the identified locations. The requester can specify the operation to be performed as well as entities having permission to perform the operation on specified subsets of the storage locations.

Abstract: System and method for maintaining temporal data in data storage at the logical device level. Embodiments of the temporal volume manager may provide an interface that allows applications and/or application agents to communicate with the temporal volume manager to manage and keep track of the temporal information on one or more temporal volumes. Embodiments may provide an infrastructure for applications that work on the history of data such as temporal databases, versioning file-systems/repositories, data archives, and streaming media to manage temporal data. In one embodiment, if an application does not want to use the temporal volume directly, application agents may be used to access the temporal volume. Embodiments may provide I/O controlled, application-controlled, and/or periodic checkpointing of temporal data on the temporal volume. One embodiment may provide a mechanism for generating temporal images (e.g.

Abstract: A method and system of providing cascaded replication is disclosed. According to one embodiment a method is provided in which data to be written to a data volume of a first node is replicated to a data volume of a second node and data to be written to the data volume of the second node is replicated to a data volume of a third node where at least one of the replication operations includes asynchronous data replication.