Abstract: A method for storing a data segment in a storage tier of a storage unit comprising at least two storage tiers includes receiving the data segment to be stored including metadata; receiving metadata of data segments stored in the storage unit; and determining the storage tier to store the received data segment to and a protection level dependent on the metadata received and dependent on the metadata of the received data segment.

Abstract: A method for storing a data segment in a storage tier of a storage unit comprising at least two storage tiers includes receiving the data segment to be stored including metadata; receiving metadata of data segments stored in the storage unit; and determining the storage tier to store the received data segment to and a protection level dependent on the metadata received and dependent on the metadata of the received data segment.

Abstract: A storage system and a method for storing a data segment, a storage capacity manager and a method for managing a capacity of a storage unit, and a storage tier relocation manager and a method for relocating a data segment. The storage system includes at least two storage tiers, an access pattern evaluator, a classification unit, a selector, and logic. The storage capacitor manager includes a monitoring unit and capacity managing unit. The storage tier relocation manager includes a target storage tier, the data segment relocated to the target storage tier, and a protection measure.

Abstract: A method for operating a computer memory and a storage device. The memory is organized to store data in units of such memory. For each unit of a set of units a wear level of the unit is determined. A maximum wear level among the wear levels is determined. A suggestion of a subset of one or more units for being selected for data erasure is received and at least one unit in the subset is identified for subsequent data erasure, a wear level (c(i)) of which units (i) is less than the maximum wear level (c_max).

Abstract: A device and method for determining number of storage devices for each of plurality of storage tiers and assignment of data to be stored in the plurality of storage tiers. The device computes an optimized number of storage devices for each tier including a classifier, which receives units as input data to be stored in the system. Based on the characteristics of the storage devices, the device outputs a data-unit-to-storage tier assignment. An optimizer receives data-unit-to-storage tier assignment from the classifier and a cost budget for the system. Thereafter, an output for the number of storage devices for each storage tier is calculated. A method for determining number of storage devices for each of a plurality of storage tiers and assignment of data to be stored in the plurality of storage tiers are also provided.

Abstract: A method, computer program product, and storage device for managing a computerized memory for storing data are disclosed. Data updates are performed by writing data updates out-of-place where data updates to outdated data are written to a subunit different from a subunit containing the outdated data. The subunit containing the outdated data is invalid, while a subunit containing up-to-date data is a valid subunit. A data structure is maintained for providing the m units in a sorted way. A first subset of n units is selected out of the set of m units with n<m by selecting units from n positions in the data structure. It is searched in the first subset to identify a unit that matches a predetermined criterion, and data of valid subunits of a unit identified in the first subset is rewritten into at least another unit.

Abstract: An apparatus and method for a memory controller for managing scheduling requests in a solid state memory device. The memory includes a set of units wherein a unit within the set of units is erasable as a whole by a unit reclaiming process resulting in a free unit available for writing data to. The memory controller further includes a first queue for queuing user requests for reading and/or writing data from/to the memory, and a second queue for queuing unit reclaiming requests for executing the unit reclaiming process. A scheduler is provided for selecting user requests from the first queue and unit reclaiming requests from the second queue for execution according to a defined ratio. The defined ratio is a variable ratio, is dependent on the current number of free units, and permits the memory controller to select requests from both the first queue and the second queue.

Abstract: A method for operating a computer memory. The memory is organized to store data in units of such memory. For each unit of a set of units a wear level of the unit is determined. A maximum wear level among the wear levels is determined. A suggestion of a subset of one or more units for being selected for data erasure is received and at least one unit in the subset is identified for subsequent data erasure, a wear level (c(i)) of which units (i) is less than the maximum wear level (c_max).

Abstract: A mechanism is provided for controlling a solid state storage device in which the solid state storage comprises erasable blocks each comprising a plurality of data write locations. Input data is stored in successive groups of data write locations, each group comprising write locations in a set of erasable blocks in each of a plurality of logical subdivisions of the solid state storage. The input data is error correction encoded such that each group contains an error correction code for the input data in that group. Metadata, indicating the location of input data in the solid state storage, is maintained in memory. An indication of validity of data stored in each data write location is also maintained. Prior to erasing a block, valid input data is recovered from the group containing write locations in that block. The recovered data is then re-stored as new input data.

Abstract: In a solid state memory device, codewords stored in a unit of the memory device are decoded using an error correcting iterative decoding process. An average number of iterations needed for successfully decoding codewords of the unit is determined, and the average number of iterations is monitored. The average number of iterations can be taken as a measure of wear of the subject unit.

Abstract: A method for wear-leveling cells, pages, sub-pages or blocks of a memory such as a flash memory includes receiving (S10) a chunk of data to be written on the cell, page, sub-page or block of the memory; counting (S40), in the received chunk of data, a number of times a given type of binary data ‘0’ or ‘1’ is to be written; and distributing (S50) the writing of the received chunk of data among cells, pages, sub-pages or blocks of the memory such as to wear-level the memory with respect to the number of the given type of binary data ‘0’ or ‘1’ counted in the chunk of data to be written.

Abstract: A method, computer program product, and storage device for managing a computerized memory for storing data are disclosed. Data updates are performed by writing data updates out-of-place where data updates to outdated data are written to a subunit different from a subunit containing the outdated data. The subunit containing the outdated data is invalid, while a subunit containing up-to-date data is a valid subunit. A data structure is maintained for providing the m units in a sorted way. A first subset of n units is selected out of the set of m units with n<m by selecting units from n positions in the data structure. It is searched in the first subset to identify a unit that matches a predetermined criterion, and data of valid subunits of a unit identified in the first subset is rewritten into at least another unit.

Abstract: An apparatus and method for a memory controller for managing scheduling requests in a solid state memory device. The memory includes a set of units wherein a unit within the set of units is erasable as a whole by a unit reclaiming process resulting in a free unit available for writing data to. The memory controller further includes a first queue for queuing user requests for reading and/or writing data from/to the memory, and a second queue for queuing unit reclaiming requests for executing the unit reclaiming process. A scheduler is provided for selecting user requests from the first queue and unit reclaiming requests from the second queue for execution according to a defined ratio. The defined ratio is a variable ratio, is dependent on the current number of free units, and permits the memory controller to select requests from both the first queue and the second queue.

Abstract: A method and apparatus for managing write operations in memory. The method includes a memory including units, each of the units including subunits. Data updates are written “out-of-place”, in that new data does not overwrite the memory locations (subunits) where the data is currently stored. The at least one subunit containing the outdated data is marked as invalid. As a result, a subunit can contain up to date data in a valid subunit next to invalid subunits. For reclaiming units for erasure, it is searched amongst the units to identify a unit or units that match a predetermined criterion. The data of valid subunits of such identified unit is rewritten to another unit or units.

Abstract: A method, computer program product, and storage device for managing a computerized memory for storing data are disclosed. Data updates are performed by writing data updates out-of-place where data updates to outdated data are written to a subunit different from a subunit containing the outdated data. The subunit containing the outdated data is invalid, while a subunit containing up-to-date data is a valid subunit. A data structure is maintained for providing the m units in a sorted way. A first subset of n units is selected out of the set of m units with n<m by selecting units from n positions in the data structure. It is searched in the first subset to identify a unit that matches a predetermined criterion, and data of valid subunits of a unit identified in the first subset is rewritten into at least another unit.

Abstract: An apparatus and method for a memory controller for managing scheduling requests in a solid state memory device. The memory includes a set of units wherein a unit within the set of units is erasable as a whole by a unit reclaiming process resulting in a free unit available for writing data to. The memory controller further includes a first queue for queuing user requests for reading and/or writing data from/to the memory, and a second queue for queuing unit reclaiming requests for executing the unit reclaiming process. A scheduler is provided for selecting user requests from the first queue and unit reclaiming requests from the second queue for execution according to a defined ratio. The defined ratio is a variable ratio, is dependent on the current number of free units, and permits the memory controller to select requests from both the first queue and the second queue.

Abstract: Machines, systems and methods for optimizing data replication in a distributed storage network, the method comprising determining a need to create a replica for a data item in a remote failure zone in a data storage network; creating a temporary replica of the data item in a local failure zone defined in the data storage network, in response to determining that it is beneficial to create the temporary replica in the local failure zone based on a cost versus reliability improvement analysis; attempting to create the replica in the remote failure zone; and removing the temporary replica from the local failure zone, in response to successfully creating the replica in the remote failure zone.

Abstract: A computing device writes data across storage devices in an erasure-coded system. The computing device computes data blocks and parity blocks from data and computes a portion of the data to be stored in the system. The computing is performed by one or more controllers included in a redundant array of an independent disks controller. The computing device provides the locations of the data blocks and the parity blocks in storage devices of an erasure-coded system. The location is determined using one or more placement nodes. The placement nodes are configured for managing placement schemes of data blocks and parity blocks on the storage devices.

Abstract: A method and apparatus for decoding a codeword received from a flash memory. The flash memory comprises multi-level flash memory cells, wherein each multi-level flash memory cell stores one symbol of the codeword. An ECC decoder is arranged for decoding the codeword into a decoded codeword and correcting a maximum number of errors. The method determines the number of errors in the codeword. If the number of errors is more than the maximum number of errors that the ECC decoder can correct, the method generates modified codewords, calculates a corrective effect of a modified codeword, and determines a decoded codeword based on the corrective effect.

Abstract: A data storage system including at least one memory device array including memory devices for storing data; and a storage subsystem controller for performing a method for operating the memory devices within the memory device array by relocating parity entities from a first memory device to a spare memory device replacing a failed memory device, and by storing one or more of reconstructed data entities on the first memory device.