Abstract: A computer-implemented method, according to one embodiment, includes: selecting strips from each storage unit for a given erasure code stripe such that the given erasure code stripe includes at most one strip from a high failure rate region of the respective storage unit, where each of the storage units include high and low failure rate regions. The selected strips are organized such that a number of each strip in the given erasure code stripe is offset from the remaining strips by an amount that is greater than a total number of strips in the high failure rate regions. The organized selected strips are further mapped to form the given erasure code stripe such that the high failure rate regions on each storage unit are mapped to one or more sequentially numbered strips, and the low failure rate regions are mapped to additional sequentially numbered strips.

Abstract: A computer-implemented method according to one embodiment includes initiating a read-modify-write (RMW) operation; assigning the RMW operation to a thread; identifying a storage device associated with the RMW operation; assign a log block within the storage device to the thread; determining a free shadow block location within the storage device; creating a copy of data to be written to the storage device during the RMW operation; writing the copy of the data to the free shadow block location within the storage device; updating the log block within the storage device to point to the free shadow block location to which the copy of the data is written; and writing the data to one or more blocks of a home area of the storage device.

Abstract: A computer-implemented method includes receiving deduplication information at a storage system. The deduplication information is accessible to the storage system for performing operations thereon. The deduplication information includes signatures associated with portions of client data. The method also includes receiving the client data encrypted with a client secret key. The client secret key is unavailable to the storage system. The method includes deduplicating data chunks stored in the storage system against chunks of the client data, wherein the client data chunks are selected from the client data for deduplication using the deduplication information.

Abstract: Embodiments of the invention relate to systematic migration of data. Data is streamed to data storage and stored in a virtual storage device (VSD). Stored data is systematically migrated from the VSD to a higher density VSD, while streaming of data is also switched to the higher density VSD. Source and target data extents are maintained and merged upon completion of the data migration, together with linking the streamed data blocks with the migrated data blocks in the order presented in the input stream.

Abstract: A method in one embodiment includes writing first data to a first memory device of a memory array at a first number of writes per unit time; writing second data to a second memory device of the memory array at a second number of writes per unit time; and skewing expected wearout times of the memory devices by making the second number of writes per unit time less than the first number of writes per unit time. A method in another embodiment includes writing first data to a first memory device of a memory array; writing second data to a second memory device of the memory array; and skewing expected wearout times of the memory devices by making a number of available storage units on the second memory device less than a number of available storage units on the first memory device.

Abstract: A method according to one embodiment includes writing monitor data to at least one block of a memory device having finite endurance and/or retention; reading the monitor data after a period of time; determining a retention behavior of the at least one block based on the reading; and outputting a result of the determining. A memory device according to one embodiment includes a plurality of memory blocks having finite endurance and/or retention, at least one of the blocks having monitor data written therein; and circuitry for addressing the blocks. A system according to one embodiment includes a memory device having finite endurance and/or retention, the memory device comprising: a plurality of memory blocks, at least one of the blocks having monitor data written therein, wherein the at least one block has been written to a plurality of times prior to writing the monitor data; and circuitry for addressing the blocks.

Abstract: A method according to one embodiment includes gathering information about monitor data from a plurality of memory devices having finite endurance and/or retention, the monitor data being (i) data of known content stored in dedicated memory cells of known write cycle count, and (ii) write protected for preventing the monitor data from being overwritten with user data; analyzing the monitor data information; and taking an action relating to at least one of the devices based on the analyzing. Additional systems, methods, and computer program products are also disclosed.

Abstract: Embodiments of the invention relate to a storage system cache with flash memory units organized in a RAID configuration. An aspect of the invention includes a storage system with a storage cache that includes flash memory units organized in an array configuration. The storage system further includes an array controller that manages data access and data operations for the flash memory units and organizes data as full array stripes. The storage system also includes a storage cache controller, that includes a block line manager that buffers write data to be cached for a write operation until the storage cache controller has accumulated an array band, and commits write data to the array controller as full array stripes. The storage cache controller determines whether to store write data for a write in the storage cache and/or in the primary storage device and whether to access read data from the storage cache or from the primary storage device.

Abstract: The error tolerance of an array of m storage units is increased by using a technique referred to as “dodging.” A plurality of k stripes are stored across the array of storage units in which each stripe has n+r elements that correspond to a symmetric code having a minimum Hamming distance d=r+1. Each respective element of a stripe is stored on a different storage unit. An element is selected when a difference between a minimum distance of the donor stripe and a minimum distance of a recipient stripe is greater or equal to 2. The selected element is also stored on a storage unit having no elements of the recipient stripe. A lost element of the recipient stripe is then rebuilt on the selected element.

Abstract: A method according to one embodiment includes gathering monitor data information from a memory device having finite endurance and/or retention, the monitor data being data of known content stored in dedicated memory cells of known write cycle count; analyzing the monitor data information; estimating a reliable life of the memory device or portion thereof based on the analysis; tracking a rate of change of at least a highest cycle count of user data; estimating when the reliable life of the memory device or portion thereof will be expended based on the tracking and the estimating; and taking an action prior to the reliable life of the memory device or portion thereof being expended. Additional systems, methods, and computer program products are also disclosed.

Abstract: A method according to one embodiment includes gathering information about monitor data from a plurality of memory devices having finite endurance and/or retention, the monitor data being (i) data of known content stored in dedicated memory cells of known write cycle count, and (ii) write protected for preventing the monitor data from being overwritten with user data; analyzing the monitor data information; and taking an action relating to at least one of the devices based on the analyzing. Additional systems, methods, and computer program products are also disclosed.

Abstract: A method according to one embodiment includes gathering monitor data information from a plurality of memory devices having finite endurance and/or retention, the monitor data being data of known content stored in dedicated memory cells of known write cycle count; analyzing the monitor data information; and taking an action relating to at least one of the devices based on the analyzing. Additional systems, methods, and computer program products are also disclosed.

Abstract: A method for rearranging data blocks in a data storage system when adding new storage devices to create an expanded data storage system. A temporary configuration is selected for which the exchange of one or more data blocks between the temporary configuration and the source configuration produces the destination configuration before identifying and exchanging data blocks between the temporary configuration and the source configuration to produce the destination configuration. A single data element transfer chain embodiment provides superior performance in an embodiment that maintains (does not reduce) the source array data storage efficiency at the destination array after scaling. When adding a single new device to an existing array, the required data movement is minimized and does not exceed the capacity of the new device.

Abstract: Embodiments of the invention relate to systematic migration of data. Data is streamed to data storage and stored in a virtual storage device (VSD). Stored data is systematically migrated from the VSD to a higher density VSD, while streaming of data is also switched to the higher density VSD. Source and target data extents are maintained and merged upon completion of the data migration, together with linking the streamed data blocks with the migrated data blocks in the order presented in the input stream.

Abstract: A data storage subsystem that includes three data storage units, three check storage units, and an array controller coupled to the three data and three check storage units can tolerate failure of any three data and check storage units failures can be occur before data stored on the data storage subsystem is lost. Information is stored on the data storage subsystem as a symmetric Maximum Distance Separation code, such as a Winograd code, a Reed Solomon code, an EVENODD code or a derivative of an EVENODD code. The array controller determines the contents of the check storage units so that any three erasures of the data storage units and the check storage units can be corrected by the array controller. The array controller updates a block of data contained in any one of the data storage units and the check storage units using only six IO operations.

Abstract: An optimum pathway to data stored on a data storage system having N storage devices and more than N pathways is determined in response to a read request for the data. A sorter separates the read request into an appropriate segment size for sending to the storage devices of the data storage system. An assigner generates the set of read permutations satisfying the read request. A read permutation is selected based on a metric. A collector receives the requested data from the N storage devices in response to the selected read permutation being sent to the storage devices.

Abstract: An optimum pathway to data stored on a data storage system having N storage devices and more than N pathways is determined in response to a read request for the data. A sorter separates the read request into an appropriate segment size for sending to the storage devices of the data storage system. An assigner generates the set of read permutations satisfying the read request. A read permutation is selected based on a metric. A collector receives the requested data from the N storage devices in response to the selected read permutation being sent to the storage devices.

Abstract: A method according to one embodiment includes writing monitor data to at least one block of a memory device having finite endurance and/or retention; reading the monitor data after a period of time; determining a retention behavior of the at least one block based on the reading; and outputting a result of the determining. A memory device according to one embodiment includes a plurality of memory blocks having finite endurance and/or retention, at least one of the blocks having monitor data written therein; and circuitry for addressing the blocks. A system according to one embodiment includes a memory device having finite endurance and/or retention, the memory device comprising: a plurality of memory blocks, at least one of the blocks having monitor data written therein, wherein the at least one block has been written to a plurality of times prior to writing the monitor data; and circuitry for addressing the blocks.

Abstract: A method in one embodiment includes writing first data to a first memory device of a memory array at a first number of writes per unit time; writing second data to a second memory device of the memory array at a second number of writes per unit time; and skewing expected wearout times of the memory devices by making the second number of writes per unit time less than the first number of writes per unit time. A method in another embodiment includes writing first data to a first memory device of a memory array; writing second data to a second memory device of the memory array; and skewing expected wearout times of the memory devices by making a number of available storage units cm the second memory device less than a number of available storage units on the first memory device.

Abstract: A method according to one embodiment includes gathering monitor data information from a plurality of memory devices having finite endurance and/or retention, the monitor data being data of known content stored in dedicated memory cells of known write cycle count; analyzing the monitor data information; and taking an action relating to at least one of the devices based on the analyzing. Additional systems, methods, and computer program products are also disclosed.