Abstract: For a data copying operation, data compression using constant number-of-track-groups and a thinly provisioned target device facilitates incremental updates where the size of the compressed data on the target device changes. Compressed data is written to the same LBA as the beginning of the source device chunk cluster LBA (1:1 mapping of data start). A termination string or other demarking device is used to identify space freed on the target device resulting from compression. During an incremental update only changed chunk clusters are changed, and freed space is changed accordingly if necessary.

Abstract: Example embodiments of the present invention relate to a method, a system, and a computer program product for leveraging secondary storage for primary storage snapshots. The method includes creating a current first snapshot of a volume at a current first time in a primary storage. The method then may determine differences between the current first snapshot at the current first time and a previous second snapshot created at a previous second time. The differences then may be sent to a secondary storage.

Abstract: When migrating data, a first message is received at a target data storage system from a source data storage system. The target data storage system includes a data storage optimizer that performs automated data movement optimizations. The first message requests a reservation of a first amount of storage on a first storage tier for performing a data migration to migrate data from the source to the target data storage system. A first capacity limit of the first storage tier is reduced by the first amount thereby representing the reservation of the first amount of storage for performing the data migration. If the first storage tier does not include an amount of available storage of at least the first amount, processing is performed to increase the amount of available storage of the first storage tier.

Abstract: Predictors of future application activity/inactivity are used in combination with monitored data access activity to prompt movement of data between tiers of storage. The apparent amount of activity for data associated with an application that is expected to become active to be increased even before data associated with that application becomes active. Further, the apparent amount of activity for data associated with an application that has become inactive is rapidly decreased by overriding algorithms that control rate of change to counter thrashing.

Abstract: Described are techniques for destaging data. Write data for write operations are stored in cache page(s). The cache may be partitioned into cache pages and write data stored thereon may be marked as write pending denoting that write data needs to be written out to physical storage. Weight values may be determined for the cache pages in accordance with factors. A first cache page may be selected having a highest such weight value where the selected first cache page includes at least some write data marked as write pending. The write data of the selected first cache page may be destaged to physical storage.

Abstract: In one aspect, a method includes migrating a first device on a first array to a second device on a second storage array. The migrating includes instructing an asset to scan the first array and the second array for the first device and the second device, reading a work buffer on the second array, sending a request to the work buffer for a chunk of the first device to copy to the second device, reading assigned chunk from the first device, copying the assigned chunk to the second device and notifying the work buffer that the copying of the assigned chunk was successful.

Abstract: Guaranteeing space availability for thin devices includes reserving space without committing, or fully pre-allocating, the space to specific thin device ranges. Space may be held in reserve for a particular set of thin devices and consumed as needed by those thin devices. The system guards user-critical devices from running out of space, for example due to a “rogue device” scenario in which one device allocates an excessive amount of space. The system uses a reservation entity, to which a thin device may subscribe, which reserves space for the thin device without allocating that space before it is need to service an I/O request.

Abstract: Exemplary methods for improving cache utilization include in response to receiving a request to store data, storing the data in one of a plurality of cache slots of a cache. In one embodiment, the methods further include after storing the data, setting a status of the cache slot as write pending to indicate that the cache slot contains data which needs to be written to a corresponding destination storage device. The methods include determining an eviction type of the cached data based on whether the destination storage device is a local storage device or a remote storage device. In one embodiment, after copying data from the cache slot to the corresponding destination storage device, marking the cache slot with the determined eviction type. In response to receiving another request to store data, evicting at least one of the cache slots based on the eviction type.

Abstract: A replica site is restored to a selected point in time by determining data state at the selected point in time, writing data indicative of that data state to the replica site storage array, and moving extents of the data written to the replica site storage array to selected tiers in order to achieve a predetermined level of performance. A journal of statistical meta data indicative of IO activity may be used to select the tiers.

Abstract: A computer-executable method, system, and computer program product of managing a hierarchical data storage system, wherein the data storage system includes a first level of one or more hosts, a second level of one or more storage appliances, and a data storage array, the computer-executable method, system, and computer program product comprising receiving an I/O request from a first host of the one or more hosts, wherein the I/O request relates to a portion of data on the data storage array, analyzing the I/O request to determine a status of the portion of data on the data storage system, based on the determination, providing an update to a second host of the one or more hosts based on the I/O request, wherein the portion of data is cached on the second host of the one or more hosts, and processing I/O request by sending I/O request to data storage array.

Abstract: A virtual storage unit from one data storage system may be migrated to another data storage system. Utilization impacts on system resources by one or more virtual storage units on multiple data storage systems may be quantified, for each data storage system as a whole, or for a functional component of each data storage system. Based on these quantifications, multiple “what-if” scenarios may be considered to determine the consequences of migrating one or more virtual storage units from one of the data storage systems to another one of the data storage systems. If it is determined that a virtual storage unit is to be migrated, a live migration may be performed such that one or more hosts maintain access to the data of the virtual storage unit while the virtual storage unit is being migrated.

Abstract: A system and techniques are provided for evaluating front end activity of a storage device in connection with storage tiering and management operations at the back end without the need to collect new sub-LUN metrics/statistics on the front end or querying the front end. The system avoids demotions of extents that are hot on the front end even when seemingly cool on the back end. The result is improved system performance since data that is hot on the front end will not be demoted to a lower storage tier. The system provides that there is little to no additional performance impact on the front end because there is no requirement to collect any new front end statistics or query the front end, and there is no increase in the meta data collected by the automated tiering system as there is no new sub-LUN metrics collected on the front end.

Abstract: Managing data in a storage system having a plurality of classes of storage includes determining an amount of data to be provided on at least one of the classes of storage according to a policy, dynamically setting a threshold according to the amount of data to be provided on the at least one of the classes or an expected performance based on the threshold, and placing data on particular classes of storage based on the threshold. Dynamically setting a threshold may include sorting data portions according to at least one score thereof and may include determining a particular score corresponding to the amount of data to be provided. The data portions may be provided in a histogram having a horizontal scale corresponding to a score value and a vertical scale corresponding to a number of data portions having a particular value.

Abstract: Described are techniques for partitioning storage of a data storage system. A plurality of storage groups is selected. Each of the plurality of storage groups includes one or more devices and is associated with an allocation policy including a first threshold specifying one of a minimum or a maximum amount of storage of a first of a plurality of storage tiers. Workload data for the plurality of storage groups is analyzed. Storage of a plurality of storage tiers is partitioned for use by the plurality of storage groups in accordance with criteria. The criteria includes workloads of the plurality of storage groups and the allocation policy associated with each of the plurality of storage groups.

Abstract: Described are techniques for processing I/O (input/output) operations. A first observed value of a first performance metric denoting any of a current workload or performance for a first physical device is determined. A target time delay for the first physical device is identified based on the first observed value of the first performance metric. The target time delay specifies a minimum time delay between consecutive host I/Os directed to the first physical device. The target time delay is enforced with respect to consecutive host I/Os directed to the first physical device.

Abstract: Example embodiments relate to a method, a system, and a computer program product for load balancing for port selection. The method includes determining a processing load for each storage port in a plurality of storage ports having variable processing power and calculating a delay characteristic for each storage port of the plurality of storage ports according to its processing load. A command then may be sent to a selected storage port of the plurality of storage ports according to the delay characteristics and a policy.

Abstract: Example embodiments of the present invention relate to a method and a system for improving performance of flash cache memory, such as in a host of a storage environment, for example, by preventing a cache cell from reaching an operation limit. The method includes determining that a number of operations to a first cell of a flash memory has reached a threshold and managing the flash memory according to the determination to prevent a failure of a second cell of the flash memory.

Abstract: In one aspect, a method includes receiving write I/Os for storage in a primary storage array, splitting the write I/Os to a replica site, storing the write I/Os for storage in the storage array in a cache, periodically de-staging the write I/Os in the cache to a volume and after a cache data loss, restoring lost write I/Os from the cache by using the write I/Os split to the replica site.

Abstract: A storage node uses storage descriptors for provisioning, monitoring and reporting. The storage descriptors indicate available storage resource capabilities and storage resource requirements for particular applications or types of applications using a common set of metrics. The storage node scales requirements to approximate a particular deployment scenario and then compares available capabilities and requirements as indicated by the storage descriptors.

Abstract: A method system and program product for sending a hint relating access requests of data stored on a storage array from a server to the storage array, receiving the hint at the storage array, and updating information about the data stored on the storage array using the hint.