Abstract: A method a dispersed storage network (DSN) begins by detecting a missing encoded data slice storage error associated with a current revision of a storage resource mapping, where storage resources of the DSN are selected for storage of encoded data slices in accordance with a distributed agreement protocol function on an identifier of the encoded data slices utilizing the current revision of the storage resource mapping. The method continues by accessing, for one or more previous revisions, a storage resource mapping history to identify a next oldest revision of the storage resource mapping. The method continues by determining, for a location cycle, whether the missing encoded data slice is available from a previous storage resource in accordance with the identified next oldest revision of the storage resource mapping and when locating the data within the previous storage resource, facilitating migration of the missing encoded data slice.

Abstract: A method for execution by an integrity processing unit includes determining to reclaim storage capacity of a DSN memory based on utilization information. Slice age information for a plurality of sets of encoded data slices stored in the DSN memory is determined, and a plurality of sets of encoded data slices are selected based on the slice age information. All encoded data slices are identified for deletion when substantially each of the selected plurality of sets includes less than or equal to a decode threshold number of encoded data slices. A subset of encoded data slices is identified for deletion when substantially each of the selected plurality of sets includes more than the decode threshold number of encoded data slices, where removal of the subset of encoded data slices results in at least the decode threshold number of encoded data slices remaining for each selected set of encoded data slices.

Abstract: A storage method and device for a solid-state drive is provided in embodiments of the present disclosure. The method includes: configuring a checkpoint drive and a cache drive; backing up data blocks from a data drive into the checkpoint drive; and in response to the data drives being corrupted, writing into a further data drive part of the data blocks backed up into the checkpoint drive and part of data blocks in the cache drive. The number of required SSD drives can be significantly reduced with the method and device without losing the data restoration capability. In addition, the degrading performance can also be maintained at a relatively high level.

Abstract: A processor may include a register to store a bus-lock-disable bit and an execution unit to execute instructions. The execution unit may receive an instruction that includes a memory access request. The execution may further determine that the memory access request requires acquiring a bus lock, and, responsive to detecting that the bus-lock-disable bit indicates that bus locks are disabled, signal a fault to an operating system.

Abstract: A method for execution by a computing device of a dispersed storage network (DSN). The method begins with obtaining a plurality of write requests. The method continues where for a write request of the plurality of write requests, the computing device generates a vault identification and a generation number. The method continues where the computing device obtains a rounded timestamp and a capacity factor and generates a temporary object number based on the rounded timestamp and the capacity factor. The method continues where the computing device generates a temporary source name based on the vault identification, the generation number, and the temporary object number. The method continues where the computing device identifies a set of storage units of a plurality of sets of storage units of the DSN based on the temporary source name.

Abstract: A method and system for assessing resiliency of a system is provided. A fault injection system may, for each of a plurality of dimensions of a fault profile, access an indication of possible values for the dimension, which may be specified by a user. The fault injection system may, for each of a plurality of fault profiles, automatically create the fault profile by, for each of the plurality of dimensions, selecting by the computing system a possible value for that dimension. For at least some of the fault profiles, the fault injection system injects a fault based on the fault profile into the system and determines whether a failure was detected while the fault was injected.

Abstract: Examples disclosed herein relate to storage drive management. Some examples disclosed herein a storage controller may adjust failure criteria for a storage drive and determine whether to fail the storage drive based on the adjusted failure criteria. The storage controller may adjust the failure criteria based on various factors, such as the quantity of input/output (I/O) command abort attempts corresponding to the storage drive issued by a host device.

Abstract: The present disclosure provides a method and apparatus for a redundant array of independent disks, RAID. The method includes: dividing the RAID into a plurality of sub-RAIDs; generating sub-RAID metadata corresponding to each of the sub-RAIDs; and in response to a disk in the RAID being replaced, rebuilding data in a corresponding sub-RAID based on the sub-RAID metadata. The present disclosure further provides a computer readable storage medium and a storage system.

Abstract: Techniques related to cache recovery for failed database instances are disclosed. A first database instance and a second database instance share a primary persistent storage and a secondary persistent storage. Each database instance stores, in volatile memory, a respective primary cache of a respective set of data stored on the primary persistent storage. Each database instance also stores, in volatile memory, a respective set of header data. Further, each database instance moves the respective set of data from the respective primary cache to a respective secondary cache on the secondary persistent storage. Still further, each database instance stores, on the secondary persistent storage, a respective set of persistent metadata. When the first database instance becomes inoperative, the second database instance retrieves, from the secondary persistent storage, persistent metadata corresponding to data stored in a secondary cache of the first database instance.

Abstract: The disclosed technology provides for selection of a subset of available non-volatile memory devices in an array to receive a dirty cache data of a volatile cache responsive to detection of a power failure. In one implementation, the selection of the non-volatile memory devices is based on one or more predictive power parameters usable to estimate a time remaining during which a reserve power supply can support a cache offload to the selected subset of devices.

Abstract: A method for automatically detecting and diagnosing problems in computer system functioning includes determining changed objects from computer system monitoring data, calculating temporal correlations from errors and changes sequences for each changed object, identifying and ranking suspicious computer system behavior patterns from the temporal correlations, and outputting said ranked suspicious computer system behavior patterns.

Abstract: A technology is provided for call failure backoff in a computing service environment. An allowable call failure rate is defined for application programming interface (API) calls sent to one or more endpoints. Each endpoint may use a token bucket containing a plurality of tokens, wherein a single token is defined as being equal to one API call failure. A number of tokens in the token bucket are determined prior to executing an API call to the one or more endpoints. A health status of the one or more endpoints is identified according to the number of tokens in the token bucket. The API calls to the one or more endpoints having the determined number of tokens in the token bucket that are equal to zero or may be delayed for a predetermined backoff time period.

Abstract: A method for a dispersed storage network (DSN) begins by receiving a read data object request from for a data object stored as a plurality of sets of encoded data slices in a set of storage units. The method continues by selecting a read threshold number of encoded data slices for retrieval. The method continues by issuing read slice requests to at least some of the storage units of the storage set to recover the selected read threshold number of encoded data slices. The method continues by receiving read slice responses from at least some of the storage units and selecting a decode threshold number of encoded data slices. The method continues by decoding the selected decode threshold number of encoded data slices to reproduce the data and generating audit information based on the selected slices for retrieval, the received slice, and the selected slices for decoding.

Abstract: Methods, computing systems and computer program products implement embodiments of the present invention that include defining a plurality of failure domains for sets of storage devices in a storage facility, and defining, using the failure domains, one or more limitations for distributing data on the storage devices. Upon identifying a data distribution configuration for a software defined storage system that is compliant with the one or more limitations, the identified data distribution configuration can be presented to a user. The failure domains may include physical failure domains, logical failure domains, or a combination of physical and logical failure domains, and the limitations may include mandatory limitations or a combination of mandatory and non-mandatory limitations.

Abstract: Embodiments of a multiple sign controller are generally described herein. Many embodiments include a multiple sign controller system. In some embodiments, the multiple sign controller can comprise a computer, a single instance of an operating system configured to run on the computer, two or more virtual sign controller instances, one or more physical communication ports coupled to the computer, and two or more virtual ports configured to run on the single instance of the operating system. In many embodiments, a first virtual port of the two or more virtual ports can be associated with a first virtual sign controller instance of the two or more virtual sign controller instances. Other embodiments may be described and claimed.

Abstract: Described is a computer-implemented method of reordering condition checks. Two or more condition checks in computer code that may be reordered within the code are identified. It is determined that the execution frequency of a later one of the condition checks is satisfied at a greater frequency than a preceding one of the condition checks. It is determined that there is an absence of side effects in the two or more condition checks. The values of the condition checks are propagated and abstract interpretation is performed on the values that are propagated. It is determined that the condition checks are exclusive of each other, and the condition checks are reordered within the computer code.

Abstract: The arithmetic processing device includes a first memory control unit configured to control an access to a first memory, a second memory control unit configured to control an access to a second memory. The arithmetic processing device further includes a diagnostic control unit configured to sequentially diagnose parts within the first memory via the first memory control unit, and configured to sequentially store in the second memory via the second memory control unit, diagnostic results of sequentially diagnosing the parts in parallel with the diagnosing the parts via the first memory control unit.

Abstract: Systems, methods, and apparatuses for fault tolerance and detection are described. For example, an apparatus including circuitry to replicate input sources of an instruction; arithmetic logic unit (ALU) circuitry to execute the instruction with replicated input sources using single instruction, multiple data (SIMD) hardware to produce a packed data result; and comparison circuitry coupled to the ALU circuitry to evaluate the packed data result and output a singular data result into a destination of the instruction is described.

Abstract: Identification and dynamic ranking of performance issues. For an instance of a performance anti-pattern, identifying and recording information relating to a resultant performance issue, quantifying the magnitude of the performance issue, and dynamically ranking the performance issue against other performance issues.

Abstract: An event management method of attributing a seasonal fault to maintenance activity is described. The method includes identifying a sequence of fault events as a seasonal fault, and calculating an initial seasonality metric indicating a degree of seasonality of the sequence of fault events. One or more maintenance windows are identified, and then a subset of the sequence of the fault events which correspond in time with the maintenance windows are identified. A compensated seasonality metric is calculated for the sequence of fault events minus at least some of the subset of fault events. Based on determining that the compensated seasonality metric indicates a reduction in seasonality compared with the initial seasonality metric, an indication that the sequence of fault events is associated with maintenance activities is generated.