Abstract: A storage system is provided. The storage system includes a first storage cluster, the first storage cluster having a first plurality of storage nodes coupled together and a second storage cluster, the second storage cluster having a second plurality of storage nodes coupled together. The system includes an interconnect coupling the first storage cluster and the second storage cluster and a first pathway coupling the interconnect to each storage cluster. The system includes a second pathway, the second pathway coupling at least one fabric module within a chassis to each blade within the chassis.

Abstract: Managing an application's resource stack, including: detecting, in dependence upon one or more storage system metrics, an occurrence of a storage system performance anomaly; and responsive to detecting the storage system performance anomaly, identifying, in dependence upon codified relationships between one or more storage system metrics and one or more elements in the application stack that are external to the storage system, a root cause of the storage system performance anomaly.

Abstract: A storage network receives data and a corresponding task, selects a storage units for the task, determines whether the data slice is locally available and when the data slice is not locally available, determines whether a redundant data slice is available from another storage unit. When the redundant data slice is not available from another storage unit, the storage network facilitates rebuilding the data slice to produce a rebuilt data slice by retrieving a decode threshold number of data slices corresponding to the data slice, decoding the decode threshold number of data slices to reproduce a data segment and re-encoding the data segment to produce a pillar width number of data slices that includes the rebuilt data slice.

Abstract: A method for use in a distributed storage network including a distributed storage network (DSN) memory, which in turn includes multiple storage units, includes determining storage parameters associated with error-encoded data slices generated from data to be stored in the DSN memory. The storage parameters include information indicating a read-threshold number of error-encoded data slices required to recover the data. The method further includes distributedly storing the error-encoded data slices among the plurality of storage units so that the number of the error-encoded data slices stored in any particular storage unit is chosen so that in the event of a failure of any individual storage unit, at least a read-threshold number of error-encoded data slices are still accessible from the remaining storage units.

Abstract: Ensuring resiliency to storage device failures in a storage system, including: determining a number of storage device failures within a particular write group that are to be tolerated by the storage system; for a plurality of datasets stored within the storage system, writing each dataset to at least a predetermined number of storage devices within the particular write group, wherein the predetermined number of storage devices is greater than the number of storage device failures within the particular write group that are to be tolerated by the storage system; and responsive to recovering from a system interruption: determining a number of readable storage devices that contain a copy of the dataset; and if the number of readable storage devices that contain a copy of the dataset is not greater than the number of failures that are to be tolerated, writing the dataset to one or more additional storage devices.

Abstract: A system and method for efficiently maintaining metadata stored among a plurality of solid-state storage devices. A data storage subsystem supports multiple mapping tables. Records within a mapping table are arranged in multiple levels. Each level stores at least pairs of a key value and a physical pointer value. The levels are sorted by time. New records are inserted in a created new highest (youngest) level. No edits are performed in-place. A data storage controller determines both a cost of searching a given table exceeds a threshold and an amount of memory used to flatten levels exceeds a threshold. In response, the controller incrementally flattens selected levels within the table based on key ranges. After flattening the records in the selected levels within the key range, the records may be removed from the selected levels. The process repeats with another different key range.

Abstract: A system and method comprising: receiving a request to write data stored at a first range of a first volume to a second range of a second volume, where first metadata for the first range of the first volume is associated with a range of physical addresses where the data is stored in the storage system; and responsive to receiving the request: creating second metadata for the second range of the second volume, wherein the second metadata is associated with the range of physical addresses where the data is stored in the storage system; and associating the second volume with the second metadata.

Abstract: A method begins by a processing module of a storage network analyzing storage network memory for a level of usability and based on the analyzing, selecting alternative memory available for receipt of encoded data slices stored in current memory, where a data object is segmented into a plurality of data segments and a data segment of the plurality of data segments is dispersed error encoded in accordance with dispersed error encoding parameters to produce a set of encoded data slices. The method continues with the processing module determining whether to move encoded data slices from current memory to alternative memory and based on a determination to move slices, allocating alternative memory. Finally, the processing module moves at least some encoded data slices from a current memory to alternate memory and updates a memory assignment mechanism for the at least some encoded data slices.

Abstract: A virtualized copy-by-reference includes: receiving, from a first computer system, a request for reference information for source data within a source volume; providing, to the first computer system, the reference information, wherein the reference information corresponds to a metadata representation of the source data; receiving, from a second computer system, a request to write the source data to a target volume, and wherein the request to write the source data indicates the reference information; and copying, using the reference information, the metadata representation of the source data to the target volume.

Abstract: A method of distributed file deletion, performed by a storage system, is provided. The method includes receiving, at the storage system, a request to delete a directory and contents of the directory and adding the directory to a first set, listed in a memory in the storage system. The method includes operating on the first set, by examining each directory in the first set to identify subdirectories, adding each identified subdirectory to the first set as a directory, and adding each examined directory to a second set listed in the memory. The method includes deleting in a distributed manner across the storage system without concern for order, contents of directories, and the directories, listed in the second set.

Abstract: An illustrative method includes a data protection system determining a first compressibility metric associated with write traffic processed by a storage system, the first compressibility metric indicating an amount of storage space saved if the write traffic is compressed; determining a second compressibility metric associated with read traffic processed by a storage system, the second compressibility metric indicating an amount of storage space saved if the read traffic is compressed; determining, based on a comparison of the first compressibility metric with the second compressibility metric, that the write traffic is less compressible than the read traffic; determining, based on the write traffic being less compressible than the read traffic, that the storage system is possibly being targeted by a security threat; and performing, based on the determining that the storage system is possibly being targeted by the security threat, a remedial action with respect to the storage system.

Abstract: An illustrative method includes a data protection system determining a delta metric between a first recovery dataset generated by a storage system at a first time and a second recovery dataset generated by the storage system at a second time subsequent to the first time and determining, based on the delta metric, whether data maintained by the storage system is possibly being targeted by a security threat.

Abstract: Failure information associated with a plurality of blocks of a solid-state storage device of a plurality of solid-state storage devices is received. One or more blocks of the plurality of blocks storing uncorrectable data are identified based on the received failure information. A partial deallocation of the one or more blocks of the plurality of blocks is issued, the partial deallocation indicating that the one or more blocks store uncorrectable data. A remedial action associated with the one or more blocks of the plurality of blocks is performed.

Abstract: In some embodiments, a method for die-level monitoring is provided. The method includes distributing user data throughout a plurality of storage nodes through erasure coding, wherein the plurality of storage nodes are housed within a chassis that couples the storage nodes. Each of the storage nodes has a non-volatile solid-state storage with non-volatile memory and the user data is accessible via the erasure coding from a remainder of the storage nodes in event of two of the storage nodes being unreachable. The method includes producing diagnostic information that diagnoses the non-volatile memory on a basis of per package, per die, per plane, per block, or per page, the producing performed by each of the plurality of storage nodes. The method includes writing the diagnostic information to a memory in the storage cluster.

Abstract: A method includes identifying an independent data object of a plurality of independent data objects for retrieval from dispersed storage network (DSN) memory. The method further includes determining a mapping of the plurality of independent data objects into a data matrix, wherein the mapping is in accordance with the dispersed storage error encoding function. The method further includes identifying, based on the mapping, an encoded data slice of the set of encoded data slices corresponding to the independent data object. The method further includes sending a retrieval request to a storage unit of the DSN memory regarding the encoded data slice. When the encoded data slice is received, the method further includes decoding the encoding data slice in accordance with the dispersed storage error encoding function and the mapping to reproduce the independent data object.

Abstract: A processing system operates by: storing a data segment as a set of encoded data slices, wherein the set of encoded data slices are dispersed storage error encoded and stored in at least one storage unit of a storage network; receiving, from a requestor, an access request associated with the data segment; detecting an access anomaly associated with the access request, the access anomaly having one of a plurality of anomaly types; denying the access request in response to detecting the access anomaly; generating, based on the one of the plurality of anomaly types, an anomaly detection indicator identifying the requestor; and sending the anomaly detection indicator to other devices of the storage network.

Abstract: Controlling access to sensitive data in a shared dataset, including: identifying, for a dataset stored at a first location, a second location for replicating a portion of the dataset; replicating, from the first location to the second location, the portion of the dataset, wherein the portion of the dataset does not include all data in the dataset; detecting that additional data has been added to the portion of the dataset stored in the second location; and replicating, from the second location to the first location, the additional data that has been added to the portion of the dataset stored in the second location.

Abstract: A storage system determines source addresses, and destination addresses in a storage system, for network traffic. The storage system determines a hash algorithm, from a plurality of hash algorithms. The hash algorithm is to be used across the source addresses for load-balancing the network traffic to the destination addresses. The storage system determines that the hash algorithm more closely meets one or more load-balancing criteria than at least one other hash algorithm, of the plurality of hash algorithms. The storage system distributes the network traffic from the source addresses to the destination addresses in the storage system, with load-balancing according to the determined hash algorithm.

Abstract: An illustrative method includes a storage system receiving attribute data representative of one or more attributes of a known attack against data maintained by a target system other than the storage system, updating an extensible attack monitoring process executed by the storage system with the attribute data, and monitoring, using the extensible attack monitoring process updated with the attribute data, storage operation requests of the storage system for one or more attributes that match the one or more attributes of the known attack.

Abstract: A system and method for managing tables in a storage system is described.