International Business Machines Corporation

Mark Anthony Sovik

Robert Frederic Kern

William Frank Micka

Ronald Maynard Kern

Donald Lee Miller

Matthew Joseph Anglin

Ahmad Zandi

Donald Paul Warren, Jr

Anthony Steve Pearson

Pong-sheng Wang

Brian J Smith

Nancy Y Young

Data compression efficacy in a data storage system is analyzed, and data compression modified in accordance with the results of such analysis, thereby saving otherwise wasted processor time when data compression is poor. Multiple input data blocks are received for storage in a data storage subsystem, and a predetermined compression process is applied thereto. Application of the predetermined compression process is evaluated according to a predetermined compression criteria. If the compression fails to satisfy the predetermined compression criteria, application of the predetermined compression process ceases.

On-line data compression analysis and regulation

A storage controller conditions host access to stored data objects upon host provision of a proposed key with matching or other prescribed relation to a security key stored in host-inaccessible metadata that is associated with the stored data object. The security key may be established upon writing the data or allocating storage space, for example. This enables the storage controller or device to be attached directly to a network without compromising security or having to add an intermediate server to perform security functions. Another implementation concerns sound recording playback devices that only play sound tracks for which the user has purchased an appropriate security key.

Storage controller conditioning host access to stored data according to security key stored in host-inaccessible metadata

Data is rapidly restored from a backup copy, and user access of the restored data further expedited by providing on-demand output of logged changes to the backup data. Contents of the backup data are the same as contents of corresponding primary data at a designated time when the backup data was created. If any changes to the primary data are received by the system after creating the backup copy, the changes are stored by the system in a change log. In one embodiment, where the system stores changes in multiple logs, the logs may be consolidated and sorted according to an appropriate schedule. Whenever primary data becomes unavailable, the system starts to apply logged changes to the backup copy right away, using the consolidated and sorted change log. When the system receives user requests to access the primary data, the system determines whether the log contains any changes that have not been applied to the backup data. If the log contains un-applied changes, the storage system provides the requesting user with an output of the most recent logged change from the log. On the other hand, if the log does not contain any un-applied changes, the storage system provides the requesting user with an output of the requested data from the backup data.

Method and apparatus for rapid data restoration including on-demand output of sorted logged changes

A storage-and-host-controller-managed outboard data management tool is described wherein the host controller defines logical paths between various storage controllers and data storage devices, and the storage controller manages the movement of data to and from the various data storage devices while only sending data to the host processorg if necessary.

Host storage management control of outboard data movement

A host-independent storage facility selectively provides data-dependent security by initially storing a security key in association with a storage region, where that key must be presented by any host seeking access to the region. The storage system includes a storage controller coupled to a digital data storage and one or more hosts. Initially, the controller receives a set-access-key command from one of the hosts, identifying a storage region, an operation parameter identifying prohibited types of storage operations, and a reference access key. The controller stores the access key and the operation parameter in a reference location associated with the identified storage region. Later, the controller may receive storage access requests from the hosts. Requests include an identification of a requested storage region, an access type, and an input access key. In response, the controller retrieves the reference access key and operation parameter associated with the requested storage region. If the requested access type is not prohibited by the operation parameter, the controller executes the storage access request. Also, if the requested access type is prohibited by the retrieved operation parameter, the controller nonetheless executes the storage access request if the input and reference access keys match.

Storage system with data-dependent security

A storage-and-host-controller-managed outboard data management tool is described wherein the host controller defines logical paths between various storage controllers and data storage devices, and the storage controller manages the movement of data to and from the various data storage devices while only sending data to the host processor if necessary.

Host storage management control of outboard data movement using push-pull operations

An expedited data backup is performed by creating a duplicate set of pointers to a current dataset already identified by an original pointer set, then designating the dataset as a backup dataset, and thereafter preventing changes to the pointed-to-data and the duplicate pointers, where changes to the current dataset are nonetheless effected by storing new data and modifying the original pointer set alone. More specifically, the backup involves an original dataset having multiple subparts residing at various original storage locations, which are pointed-to by a primary set of pointers. A virtual backup copy is created by duplicating the primary set of pointers to create a backup set of pointers. The backup set of pointers are entered in a backup list, in association with the virtual backup copy and the original dataset. To preserve the backup copy, the system prevents changes to the original dataset and the backup set of pointers. When any changes are directed to subparts of the original dataset, the system creates a changed dataset by storing the changes at one or more change storage locations and updating the primary set of pointers to identify the change storage locations along with any original storage locations still containing unchanged subparts of the original dataset. In addition to expediting data backups, fast data recovery is possible by updating the primary set of pointers to duplicate the backup set of pointers.

Method and apparatus for immediate data backup by duplicating pointers and freezing pointer/data counterparts

A data storage system includes an outboard data transfer module that directs data transfer operations without requiring substantial host involvement. This subsystem includes a host computer, one or more digital data storage devices, one or more device controllers interposed between the host computer and the storage devices, and a outboard data manager coupled to the host and the device controllers. Data transfer operations are initiated when the outboard data manager receives a data transfer request from the host. The request identifies the type of operation, resulting target format, source data residing on one or more source devices, and one or more target devices. In response to this request, the outboard data manager retrieves a copy of the source data from the source device(s), formats target data according to host instruction, and then transmits the copy to the target device(s) for storage therein. Thus, source data is copied from source to target storage device(s) via the outboard data manager without burdening the host by routing data through it. Some exemplary data transfer operations include copy, migrate, recall, backup, restore, move, defragment, reorganize, and the like.

Data storage system with outboard physical data transfer operation utilizing data path distinct from host

A system and method for demand-based data recovery operating in a computerized data processing system that includes a computer platform operable under the control of system data, including system programs, catalogs, directories, inventories and the like, and one or more user applications operable in conjunction with user data. The data processing system includes a data backup and recovery system for periodically transferring data between one or more primary data storage resources and one or more secondary data storage resources. The demand-based system and method operate to recover data from the secondary data storage resources to the primary data storage resources following a disaster event resulting in the loss of all or a portion of the data on the primary data storage resources. In accordance therewith, the system data is first recovered from the secondary data storage resources to the primary data storage resources. Execution of the one or more user applications is next commenced but the user data is not immediately recovered. Only if the application requests non-recovered user data will the requested data be recovered from the secondary data storage resources to the primary data storage resources. The demand-based system and method can be adapted to recover entire data sets (e.g. files) from a previous full backup or it can recover data subsets (e.g. records) in either a full backup mode or a change-data-only mode.

System and method for demand-base data recovery

A computer system constructs a compression dictionary for compressing a character string by interrogating an initial substring portion to determine input string characteristics that are used to select one or more dictionary segments from a library of predetermined dictionary segments individually adapted for compressing strings with particular characteristics. The initial substring portion is dynamically determined during the interrogation. A first set of dictionary segments that meet predetermined automatic selection criteria are selected and a second set of candidate dictionary segments that meet second-level selection criteria are identified for a sampling phase. During the sampling phase, the candidate dictionary segments are alternately used to compress the initial substring portion and determine compression performance statistics. The performance of the dictionary segments in the sampling phase determines which candidate dictionary segments will be added to the first selected dictionary segments, within dictionary total size limits. The first selected dictionary segments and the identified segments constitute a system-built compression dictionary that is used to compress the remainder of the input string. In this way, predetermined compression dictionaries are selected for maximum efficiency in accordance with the data actually being compressed and compression can be carried out quickly and efficiently as input data is received.

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Tucson, AZ, United States of America

Mark Anthony Sovik