Abstract: A storage system in one embodiment comprises a plurality of storage devices and a storage controller. The storage system is configured to operate as a source storage system in a replication process in which participation of a target storage system is simulated. In conjunction with the replication process, the source storage system is configured to monitor outbound replication messages, and responsive to a given one of the replication messages being designated for transmission over a particular communication link of a predetermined type, to generate a simulated response from the target storage system to the given replication message based at least in part on one or more simulation parameters specified for the replication process. The source storage system then processes the simulated response as if it were an actual response from the target storage system. The particular communication link of a predetermined type illustratively comprises a pseudo IP link.

Abstract: Systems and methods for adding backups to de-duplicated storage and for removing backups from de-duplicated storage are disclosed. Backups can be added to the de-duplicated storage with minimal reference count updates. Backup data sets can be removed without garbage collection processes being performed on the de-duplicated storage.

Abstract: In some examples, region cloning may include obtaining a clone request to clone a logical range of a source backup. The clone request may specify the source backup, a logical start offset, and a logical end offset. A source manifest associated with the logical range of the source backup may be determined. A start entry of the source manifest may be identified based on the logical start offset. The start entry may represent a start data chunk. A determination may be made as to whether the logical start offset represents an intermediate position of the start data chunk, and if so, a start partial chunk entry representing a sub-range of the start data chunk may be appended to a destination manifest. A backup of the logical range of the source backup may be generated based on the destination manifest with the appended start partial chunk entry.

Abstract: A data processing system includes multiple processing units all having access to a shared memory. A processing unit includes a processor core that executes memory access instructions including a store-conditional instruction that generates a store-conditional request specifying a store target address and store data. The processing unit further includes a reservation register that records shared memory addresses for which the processor core has obtained reservations and a cache that services the store-conditional request by conditionally updating the shared memory with the store data based on the reservation register indicating a reservation for the store target address. The processing unit additional includes a blocking state machine configured to protect the store target address against access by any conflicting memory access request during a protection window extension following servicing of the store-conditional request.

Abstract: Provided are a computer program product, system, and method for selective write control in accordance with the present description. In one aspect, a write operation which is associated with a read operation, may be selectively discarded if write operations have been disabled and if the write operation is directed to update a designated write operation acceptance area such as metadata associated with the target data set, for example. As a result, the read operation may be permitted to proceed and will not fail because the associated write operation was discarded rather than attempting to commit the write operation to the designated write operation acceptance area, thereby avoiding an error condition for a storage unit such as a volume, in which write operations have been disabled. Accordingly, applications which seek to perform read operations may be permitted to access data stored on such a volume. Other aspects are described.

Abstract: A method, an apparatus, and a system for accessing a storage device. The method includes: acquiring, by an I/O adapter, an access request from a virtual machine, where the access request carries virtual address information of a to-be-accessed storage area; generating an access instruction according to the access request, where the access instruction carries the virtual address information and an identifier of a virtual channel of the virtual machine, where the virtual channel corresponds to the virtual machine on a one-to-one basis and is used to connect the corresponding virtual machine to a storage device target, and the storage device target is configured to manage access to the storage device; and sending the access instruction to the storage device target.

Abstract: Provided are a computer program product, system, and method for managing point-in-time copies for extents of data. A point-in-time copy for at least one range of extents in at least one volume for a point-in-time copy identifier is established. Change recording information is generated indicating each of the at least one range of extents less than all of the extents in the at least one volume. An update to data in the at least one range of extents in the point-in-time copy is received and data in the source storage in the at least one range of extents to be updated is copied as changed data to the target storage. Indication is made in the change recording information of the data in the at least one range of extents that has been updated.

Abstract: One embodiment is related to a method for implementing a cache hierarchy, comprising: implementing a plurality of cache layers in the cache hierarchy; and determining a cache algorithm for each cache layer of the plurality of cache layers.

Abstract: A method of retrieving data stored in a memory associated with a dedupe module is provided. The method includes: identifying a logical address of the data; identifying a physical line ID of the data in accordance with the logical address by looking up at least a portion of the logical address in a translation table; locating a respective physical line, the respective physical line corresponding to the PLID; and retrieving the data from the respective physical line, the retrieving including copying a respective hash cylinder to the read cache, the respective hash cylinder including: a respective hash bucket, the respective hash bucket including the respective physical line; and a respective reference counter bucket, the respective reference counter bucket including a respective reference counter associated with the respective physical line.

Abstract: A system and method for increased efficiency thin provisioning of data storage. The method includes: receiving a request for storage allocation from a client device; and allocating, to the client device, at least a portion of a first storage of the plurality of storages when a garbage collector of the first storage is turned off.

Abstract: A method of operating a data storage device includes programming non-fully programmed memory blocks at a point in time when a reference time elapses from a point in time when each of the memory blocks is physically erased, acquiring a first interval and a second interval, calculating a disturb index based on the first interval and the second interval, selecting a victim block for garbage collection based on the disturb index, and copying valid page data of the victim block into a free block. The first interval is defined by a point in time when each of the memory blocks is physically erased and a point in time when each of the memory blocks is fully programmed. The second interval is an interval during which a fully programmed state is maintained after a point in time when each of the memory blocks is fully programmed.

Abstract: Methods and apparatus for filtering input data objects are provided. A computing device can receive an input data object to be filtered; e.g., compressed/decompressed, decrypted/encrypted, bit converted. The computing device can determine whether the input data object has been previously filtered. After determining that the input data object has been previously filtered, the computing device can: determine a previously filtered data size for the input data object, allocate a memory buffer to store a filtered version of the input data object based on the previously filtered data size, and filter the input data object using the memory buffer. The computing device can generate an output based on the filtered data object.

Abstract: One embodiment is related to a method for redistributing cache space, comprising: determining utility values associated with all of a plurality of clients, each client being associated with a respective utility value, the utility value being indicative of an efficiency of cache space usage of the associated client; and redistributing cache space among the plurality of clients based on the utility values.

Abstract: Techniques are described for processing multi-page write operations to maintain write level consistency. A multi-page write spanning multiple cache pages is directed to a target device and received on a first data storage system where writes to the target device are synchronously replicated to a second data storage system. On the first data storage system, each of the multiple cache pages may be synchronously replicated to the second data storage system. A lock on each of the cache pages is not released until an acknowledgement is received regarding successful replication of the cache page. On the second data storage system, requests to replicate the multiple cache pages containing write data of the multi-page write are received and processed using locks of corresponding cache pages on the second data storage system. Such techniques also handle concurrent reads and/or writes. Deadlock detection and resolution processing may be performed for concurrent writes.

Abstract: A computer implemented method, system, and computer program product comprising intercepting an interaction with a data storage capability at the abstraction layer enabled to intercept data interactions for different types of data storage capabilities; wherein the interaction changes data on the data storage capability; sending a copy of the interaction to a replication data storage capability; and sending the interaction to the data storage capability.

Abstract: One embodiment is related to a method for redistributing cache space, comprising: determining a request by a first client of a plurality of clients for additional cache space, each of the plurality of clients being associated with a guaranteed minimum amount (MIN) and a maximum amount (MAX) of cache space; and fulfilling or denying the request based on an amount of cache space the first client currently occupies, an amount of cache space requested by the first client, and the MIN and the MAX cache space associated with the first client.

Abstract: A method for a storage monitoring system including a storage device, a manager, and agents, wherein said manager: stores information about a first range of components of a first type that are among types of components included in the storage device, and that are to be monitored by a first agent of the agents, said stored information being associated with information about the first agent; notifies the first agent of the information about the first range of components to be monitored; stores information about a second range of components of the first type that are among the types of components, and that are to be monitored by a second agent of the agents, said stored information being associated with information about the second agent; and notifies the second agent of the information about the second range of components to be monitored.

Abstract: Methods and systems for managing synonyms in VIPT caches are disclosed. A method includes tracking lines of a copied cache using a directory, examining a specified bit of a virtual address that is associated with a load request and determining its status and making an entry in one of a plurality of parts of the directory based on the status of the specified bit of the virtual address that is examined. The method further includes updating one of, and invalidating the other of, a cache line that is associated with the virtual address that is stored in a first index of the copied cache, and a cache line that is associated with a synonym of the virtual address that is stored at a second index of the copied cache, upon receiving a request to update a physical address associated with the virtual address.

Abstract: A method of apportioning storage units in a dispersed storage network (DSN) includes generating storage unit apportioning data indicating a mapping of a plurality of desired numbers of storage units to a plurality of storage sites based on site reliability data. The mapping includes a first desired number of storage units corresponding to a first one of the plurality of storage sites that is greater than a second desired number of storage units corresponding to a second one of the plurality of storage sites in response to the site reliability data indicating that a first reliability score corresponding to the first one of the plurality of storage sites is more favorable than a second reliability score corresponding to the second one of the plurality of storage sites. A plurality of storage units are allocated to the plurality of storage sites based on the storage unit apportioning data.

Abstract: Sorting and storing a dataset, the dataset comprising at least one attribute. The method includes defining a set of data blocks and assigning to each data block a predefined maximum number of entries or a predefined maximum amount of storage, dividing the dataset into a sequence of multiple sub-datasets each having one value or a range of values of the attribute, wherein each pair of successive sub-datasets of the sequence are non-overlapping or overlapping at their respective extremum value of the attribute, for each sub-dataset of the multiple sub-datasets: in case the sub-dataset fully or partially fits into a data block of the defined data blocks storing the sub-dataset into at least the data block, the sub-dataset that partially fits into the data block comprising a number of entries that is smaller than a predefined maximum threshold.