Abstract: In one embodiment of the method, first and second data volumes are created. Thereafter, a first data portion of the first data volume is overwritten with a first data portion of the second data volume. A second data portion of the first data volume is overwritten with a second data portion of the second data volume. In one embodiment, the first and second data portions of the first data volume are overwritten with the first and second data portions of the second data volume, respectively, in response to a command to restore or synchronize the data contents of the first data volume to the data contents of the second data volume. A virtual point-in-time (PIT) copy of the first data volume is created after overwriting the first data portion but before overwriting the second data portion.

Abstract: A system and method for controlling the creation of stable disk images. Data is transmitted to an application program interface identifying the storage object. The application program interface returns a list with one or more methods appropriate for quiescing or for freezing the storage object.

Abstract: A system and method of characterizing a logical storage object. Information associated with the logical storage object is stored. The information includes information characterizing quiesce capabilities and split characteristics for the logical storage object. That information is transmitted to a processor and is used to characterize the logical storage object.

Abstract: An interactive system for debugging programs in which a persistent data base system responds to update queries containing debugging information from a debugging information source and to read queries on the debugging information from an interactive interface. The interactive interface produces the read queries in response to inputs from users and formats the results of the read queries as required by the user. One source of inputs is a standard Web browser for which the interactive interface functions as a Web server. The system also includes a command channel by which the source of debugging information receives commands from the interactive interface. In one embodiment, the command channel is implemented in the data base. In a disclosed implementation, the source of debugging information provides memory debugging information. Also disclosed are techniques for using an automatic memory management system to reduce memory fragmentation and heap footprint size.

Abstract: Disclosed is a method and apparatus for incrementally baking up a data volume. In one embodiment of the method, the data volume is created in a first memory, and a point-in-time (PIT) copy of the data volume is created at time T0. First data of the data volume is modified between times T0 and T1, wherein time T1 is subsequent to time T0. Second data of the data volume is copied to a second memory after time T1. The second data of the data volume is modified after the second data is copied to the second memory. Lastly, data of the PIT copy is overwritten with (1) the copy of the second data stored in the second memory and (2) the modified first data of the data volume.

Abstract: A method restores a client device of a network on major failure of the client device. The client device is incapable of automatically booting on its own. The network includes a server computer. The method includes booting the client device over the network in the restoration operation, configuring the client device according to the boot program and saved configuration states for the client device, and copying files to the client device in accordance with the configuration. The client computer has access to a storage manager application, such as a server computer of the network operating a storage management software program. All client files, including configuration files, as well as application and data files, of the client device are saved on the network by the storage manager application. The client device is booted over the network, rather than locally to the client device by boot disk or otherwise.

Abstract: A system for protecting a block in a destination storage device including a data mover operable to move data from a source storage device to the block, and a controller coupled to the data mover, the controller operable to detect an application write request to the block and to stall the application write request while a data move operation initiated by the data mover is terminated.

Abstract: A system and method for maintaining storage object consistency across a distributed storage network including a migratable repository of last resort which stores a last or only remaining data replica that may not be deleted. The method includes the steps of monitoring data requests to the repository of last resort, deciding whether to move the repository of last resort, and migrating the repository of last resort.

Abstract: A system, methods, and computer program products are disclosed for creating virtual application templates for the purpose of propagating a single application snapshot into multiple, distinct images. Snapshot virtual templates allow multiple application instances to use the same fixed resource identifier by making the resource identifier virtual, privatizing it, and dynamically mapping it to a unique system resource identifier. When a snapshot is cloned from a virtual template, the common or shared data is used exactly as is, whereas the non-sharable data is either copied-on-write, multiplexed, virtualized, or customized-on-duplication. The present invention notes access to modified resources, fixed system IDs/keys and unique process-related identifies and automatically inserts a level of abstraction between these resources and the application. The resources contained in a snapshot virtual template can be dynamically redirected at restore time.

Abstract: A computer system includes a read ahead engine that receives a sequence of read requests and performs read ahead operations in accordance with various patterns detected within the sequence of read requests. The prefetch engine may implement the method of storing a first run value indicative of the run size of a first plurality of sequential read requests, and storing a first skip value indicative of a non-sequential skip associated with a subsequent read request. The method may further include determining whether a second run value indicative of the sequential run size of a second plurality of read requests equals the first run value, and whether a second skip value indicative of another non-sequential skip associated with an additional read request equals the first skip value. If the first run value equals the second run value, and the first skip value equals the second skip value, a stride pattern is indicated, and one or more read ahead operations according to the detected stride pattern may be initiated.

Abstract: Disclosed is a method and apparatus for restoring a corrupted data volume. In one embodiment, the method includes creating a backup copy of the data volume before the data volume is corrupted. Data transactions that modify the contents of the data volume are stored in a transaction log. After detection of the data corruption, a virtual copy of the backup copy is created. Thereafter, select data transactions stored in the transaction log, are applied to the virtual copy. Data of the corrupted data volume is then overwritten with data of the backup copy and data of the virtual copy after applying data transactions to the virtual copy.

Abstract: Systems, methods, apparatus and software can utilize an indirect write driver to prevent possible error conditions associated with using a third-party copy operation directed at a storage resource. A data transport mechanism such as a data restore application initiates a third-party copy operation from a data source to a data cache. The indirect write driver monitors write commands as they pass to a storage resource driver. If a command is found to be an indirect write command, e.g., a command designed to complete the movement of data from the data cache to the storage resource, it is handled accordingly. Normal write commands are passed on to the storage resource driver. By completing the data move operation using normal storage management channels, e.g., the operating system, file system, and/or volume manager, error conditions can be avoided.

Abstract: System and method for data storage management. Embodiments may be used to perform analysis of disk-based data storage. Embodiments may provide a storage analysis mechanism for estimating storage inventory/availability risk tradeoff for data storage media for an application or group of applications. Embodiments may be used to generate storage inventory information and recommendations or requirements for pooled and/or non-pooled storage. Embodiments may be used to compare pooled storage to non-pooled storage for a plurality of applications in a storage system.

Abstract: A system and method for an election and data majority mechanism that solves problems such as bit flipping, mistracking, miscaching, and I/O status errors during real-time operations. Multiple copies of data are stored on various storage media of a data processing system. Errors that occur on the storage media or on other components of the data processing system are resolved by selecting the data with the highest frequency as the data majority. The data majority is propagated throughout the storage media to correct errors.

Abstract: In a process to restore a data volume in a first memory, a virtual point-in-time (PIT) copy of the data volume is created. Creating the virtual PIT copy includes creating first, second and third maps in memory. Each of the first, second, and third maps includes a plurality of multi-bit entries. Each of the entries of the first and second maps corresponds to a respective memory region of the first memory, while each of the entries of the third map corresponds to a respective memory region of a second memory for storing data of the virtual PIT copy.

Abstract: Disclosed is a method and apparatus for tracking in-progress writes to a data volume and a copy thereof using a multi-column bit map. The method can be implemented in a computer system and, in one embodiment, includes creating a data volume in a first memory, and creating a copy of the data volume in a second memory. In response to the computer system receiving a request to write first data to the data volume, the computer system switches the state of first and second bits of a map entry in a memory device, wherein the state of the first and second bits are switched using a single write access to the memory device.

Abstract: To achieve the foregoing, and in accordance with the purpose of the present invention, a system or network is disclosed which provides for a dynamic symbolic link (DSL) and the resolution of that DSL. The invention provides a method and apparatus that renames a first pathname to a target pathname, determines a variable within the target pathname, defines the first pathname as a symbolic link and associates the symbolic link with a virtual pathname. The present invention further defines a specification associated with the virtual pathname including associating the variable with the virtual pathname. In associating the symbolic link with the virtual pathname, the present invention further define a declaration within the virtual pathname.

Abstract: A system or network may provide for communication between two or more applications. The communication is achieved by initiating communication between a first and second application. The communication is directed from the first application to a second virtual address of the second application. An actual address associated with the second application is determined. A first data channel is established between a first computer associated with the first application and a second computer associated with the second application over a control channel, to coordinate the communication over the first data channel. The communication is then directed to the actual address associated with the second application over the data channel. Further, the first data channel is taken down and a second data channel is established to maintain communication without the knowledge of the first and second applications.

Abstract: Methods and systems to bridge storage management software are provided. A first storage management application communicates with a host and performs an analysis of a storage environment associated with the host. The first storage management application uses the analysis to determine if a storage resource interface is controlled by a second storage management application, and if so a plugin application is accessed by the first storage management application to permit the second storage management application to perform a storage management operation on behalf of the host. In one embodiment, the analysis is updated by the first storage management application upon receiving results from second storage management application, where the results reflect the processing of the storage management operation by the second storage management application.

Abstract: Systems, methods, apparatus and software can make use of standard input/output (I/O) interface commands to make information about virtual storage devices available to clients of those virtual storage devices. Where the storage virtualization is carried out using a switch, router, or other storage network appliance, the information about virtual devices is stored (and in many cases determined and/or processed) local to the device. Applications operating on the storage clients can conveniently access the information using I/O interface commands and need not have access to some or all of the software or functionality that virtualizes the storage.