摘要:
An improved storage controller and method for storing and recovering data. The storage controller includes a first cluster for directing data from a host computer to a storage device and a second cluster for directing data from a host computer to a storage device. A first cache memory is connected to the first cluster and a second cache memory is connected to the second cluster. A first nonvolatile memory is connected to the second cluster and a second nonvolatile memory is connected to the first cluster. The first and second cache memories and the first and second nonvolatile stores are thus "cross-coupled" to the first and second clusters to provide improved data recovery capability. Data is directed to the first cache and backed up to the first nonvolatile memory in a first operational mode. In the event of failure of the first nonvolatile memory, data is recovered from the first cache memory. In a particular embodiment, in the event of failure of the first nonvolatile memory, data is directed from the first cache memory to the second cache memory. The cache memories and nonvolatile stores may also be formed on separate power boundaries. By allowing for use of the first cache after failure of an associated nonvolatile memory, a system and technique for mitigating performance degradation in a storage control unit due to a failure in nonvolatile memory associated therewith may be obtained.
摘要:
A data storage system provides generalized record caching through a control unit adapted to support track caching in the upper level store of a two level memory. Dynamic reallocation of space between each type of caching in the upper store follows operating patterns of host computer systems using the data storage system. A storage controller cache has a plurality of segments. A directory data entry data structure is allocated each segment. Such allocated directory entries are used to identify tracks as cached. A plurality of unallocated directory entries are also provided. As a record is cached in a segment outside of a track slot, an unallocated directory entry is used to identify a virtual track in cache corresponding to the track of the record in the lower level store. Records from one track can thus appear in several segments outside track slots. Tracking of records to locate records least recently used is done globally over all track slots and record caching segments and locally within individual record caching segments. A mechanism is provided for identifying record slots, as they become least recently used, and dropping them from the upper level store in the face of competing demands for the space. A second mechanism identifies least recently used segments for dropping from the upper level store.
摘要:
A method and system for enhancing the efficiency of communication between one or more host computers and a storage system controller during a data search within either the associated storage systems or within the storage system controller itself. A storage system controller, coupled to one or more host computers via multiple communication channels, is utilized to control access to one or more direct access storage devices. A host computer authorizes the storage system controller to search within a range of data locations within the storage system, sets an initial location from which the data search will begin, and specifies a key field argument to search for. The host computer then permits the storage system controller to independently search the authorized range of data locations within the storage system or within cache memory within the storage system controller. The storage system controller examines multiple records within the authorized range of data locations to locate a desired record associated with the key field argument and presents a status report to the host computer only after the desired record is located or the entire range of data is searched and the desired record was not located. Allowing the storage system controller to independently search records and report status only after completion of an attempt to find a desired record within an authorized range of records minimizes communication overhead. Reducing the number of status reports presented over the communication channel enhances communication efficiency.
摘要:
Reporting on software test coverage, where a set of coverage tasks and a coverage task hierarchy have been established for a software under test (SUT). Establishing a coverage task subset, the subset including at least one coverage task hierarchy element at a level above the lowest coverage task hierarchy level. Identifying when, during a software test, a coverage task in the coverage task subset was completed. Outputting to a user the identity of those portions of the coverage task that have been completed. Refining the coverage task subset in one of the following fashions through the coverage task hierarchy in accordance with user input: depth first progression, breadth first progression.
摘要:
Disclosed is a system, method, and program for limiting input/output (I/O) requests from an application program to a storage device to facilitate the processing of data in memory. A determination is made as to whether an amount of a set of data in memory exceeds at least one threshold. At least one of multiple paths to the storage device is indicated as blocked to I/O requests from the application program. Each indicated blocked path is available for processing the set of data in memory. An I/O request from the application program is received and a determination is made as to whether the received I/O request intends to access the storage device using one indicated blocked path. The I/O request is denied access to the storage device via the blocked path.
摘要:
Control of the discard of data from cache during backup of the data. In a computer-implemented system comprising primary data storage; cache; backup data storage; and at least one processor, the processor is configured to identify data stored in the primary data storage for backup to the backup data storage, where the identified data is placed in the cache in the form of portions of the data, and where the portions of data are to be backed up from the cache to the backup storage. Upon backup of each portion of the identified data from the cache to the backup storage, the processor marks the backed up portion of the identified data for discard from the cache. Thus, the backed up data is discarded from the cache right away, lessening cache pollution.
摘要:
Provided is a system, deployment and program for resource allocation unit queuing in which an allocation unit associated with a task is classified. An allocation unit freed as the task ends is queued for use by another task in a queue at a selected location within the queue in accordance with the classification of said allocation unit. In one embodiment, an allocation unit is queued at a first end of the queue if classified in a first class and is queued at a second end of the queue if classified in said second class. Other embodiments are described and claimed.
摘要:
Provided is a method, system, deployment and program for resource allocation unit queuing in which an allocation unit associated with a task is classified. An allocation unit freed as the task ends is queued for use by another task in a queue at a selected location within the queue in accordance with the classification of said allocation unit. In one embodiment, an allocation unit is queued at a first end of the queue if classified in a first class and is queued at a second end of the queue if classified in said second class. Other embodiments are described and claimed.
摘要:
Methods, systems, and computer program products are provided for performing a secure delete operation in a wide area network (WAN) including a cache site and a home site. A method includes identifying a file for deletion at the cache site, determining whether the file has a copy stored at the home site, detecting a location of the copy at the home site prior to a disconnection event of the cache site from the home site, deleting the file from the cache site during the disconnection event, and performing a secure deletion of the copy at the home site immediately after a reconnection event of the cache site to the home site.
摘要:
Provided are a method, system, and program for simulating I/O requests to test a system coupled to an adaptor having a port used for transmitting and receiving I/O requests to the system. A user test command is received indicating an I/O test object. The adaptor processes the I/O test object indicated in the user test command to generate a sequence of simulated I/O requests and transmits the generated simulated I/O requests to the system.