Methods for assigning data storage resources are disclosed. The methods includes obtaining memory resource availability information for a plurality of physical memory devices of a dispersed storage network, determining a number of logical storage units for the dispersed storage network, determining a memory capacity level for each of the logical storage units, determining a mapping in accordance with a mapping approach of at least some of the plurality of physical memory devices to achieve a corresponding memory capacity level, and when accessing encoded data slices associated with the logical storage unit by an accessing entity, communicating slice access messages with a dispersed storage unit associated with the logical storage unit. A dispersed storage managing unit and dispersed storage network are also disclosed.

Systems and methods for storing data in a dispersed storage network using at least two information dispersal algorithms (IDA' s) having different widths and thresholds are disclosed. In multiple IDA configurations, at least two IDA's with different widths and thresholds are paired and used to store the data multiple times, where some IDA's provide wider IDA configurations that are more reliable and other IDA's provide narrower configurations with a lower threshold and lower reliability. Data can be written in the less reliable IDA configurations as a performance optimization to reduce the input/output operations necessary for reading the data. As a further optimization, the processing unit can determine to write only a subset of the IDA configurations. Similarly, dispersed storage units themselves, when reaching the capacity limits for their memory devices, can begin to delete slices they hold for some of the IDA configurations, to free up space.

Systems and methods for rebuilding encoded data slices in a dispersed storage network (DSN). In an embodiment, a data segment is dispersed storage error encoded using first dispersal parameters and differing second dispersal parameters to produce a first set of encoded data slices and a second sets of encoded data slices for storage in the DSN. A storage error is identified involving an encoded data slice of the first set of encoded data slices. When a first decode threshold number associated with the first dispersal parameters is greater than a second decode threshold number associated with the second dispersal parameters, a second decode threshold number of encoded data slices of the second set of encoded data slices is retrieved. The retrieved slices are decoded to recover the data segment, which is then re-encoded using the first dispersal parameters to generate a rebuilt encoded data slice corresponding to the storage error.

Methods and apparatus for efficiently storing and accessing secure data are disclosed. The method of storing includes encrypting data utilizing an encryption key to produce encrypted data, performing deterministic functions on the encrypted data to produce deterministic function values, masking the encryption key utilizing the deterministic function values to produce masked keys and combining the encrypted data and the masked keys to produce a secure package. The method of accessing includes de-combining a secure package to reproduce encrypted data and masked keys, selecting a deterministic function, performing the selected deterministic function on the reproduced encrypted data to reproduce a deterministic function value, de-masking a corresponding masked key utilizing the reproduced deterministic function value to reproduce an encryption key, and decrypting the reproduced encrypted data utilizing the reproduced encryption key to reproduce data.

Method and systems for selecting memory resources in a dispersed storage network (DSN) include a processing module obtaining deep statistics for one or more memory device of at least some storage units of a plurality of storage units of the DSN. The processing module also determines a performance level of the memory device based on the associated deep statistics of at least the memory device and further determines whether to access a memory device based on the associated performance level of the memory device. For example, the processing module indicates not to access the memory device when the performance level of the memory device is less than a minimum performance threshold level and selects another memory device associated with a favorable performance level. In addition to, the processing module can generate a new DSN address for new data storage where the new DSN address is associated with the another memory device.

Methods and apparatus for efficiently storing and accessing secure data are disclosed. The method of storing includes encrypting data utilizing an encryption key to produce encrypted data, performing deterministic functions on the encrypted data to produce deterministic function values, masking the encryption key utilizing the deterministic function values to produce masked keys and combining the encrypted data and the masked keys to produce a secure package. The method of accessing includes de-combining a secure package to reproduce encrypted data and masked keys, selecting a deterministic function, performing the selected deterministic function on the reproduced encrypted data to reproduce a deterministic function value, de-masking a corresponding masked key utilizing the reproduced deterministic function value to reproduce an encryption key, and decrypting the reproduced encrypted data utilizing the reproduced encryption key to reproduce data.

Managing storage systems that are synchronously replicating a dataset, including: detecting a change in membership to the set of storage systems synchronously replicating the dataset; and applying one or more membership protocols to determine a new set of storage systems to synchronously replicate the dataset, wherein the one or more membership protocols include a quorum protocol, an external management protocol, or a racing protocol, and wherein one or more I/O operations directed to the dataset are applied to a new set of storage systems.

A read cache management method and apparatus based on a solid state drive, and the method includes: determining whether a read request hits a first queue and a second queue (S101); if both the first queue and the second queue are missed, selecting and deleting an eliminated data block from the first queue (S102); if the eliminated data block is in a stored state, inserting the eliminated data block into the second queue (S103); and determining a target data block in a lower-level storage medium, and inserting the target data block into the first queue, (S104). According to the foregoing read cache management method and apparatus based on the solid state drive, a hit ratio of the solid state drive can be increased, a data write count of the solid state drive can be reduced, and service life of the solid state drive can be extended.

An out-of-range reference detection method according to an exemplary aspect of the invention includes: acquiring a mask value corresponding to a base address register number of a predetermined effective address from a mask value storage unit storing correspondence relationships between the base address register number of a base address register storing a base address of a segment and the mask value showing a size of a memory that can be continuously referred to from the base address, determining whether or not the effective address is outside the range of the mask value, and outputting a result of the determination.

Aspects of the present disclosure involve a system and method for verifying and validating accurate memory module placement on a printed circuit board. In one embodiment, the printed circuit board is configured to include actuating elements that can be used to verify correct memory module location placement on the printed circuit board. In another embodiment, the actuating elements can be used to validate accurate memory module placement. The actuating elements can be in the form of buttons that may be depressed and configured to trigger light emitting diodes (LEDs) that correspond to the slots on the printed circuit board.