International Business Machines Corporation

Pure Storage, Inc.

Tyler K Reid

Adam Michael Gray

Daniel J Scholl

Greg R Dhuse

Ilya Volvovski

Ravi V Khadiwala

Scott Michael Horan

Jason K Resch

Wesley B Leggette

Manish Motwani

Praveen Viraraghavan

Yogesh Ramesh Vedpathak

Bruno Hennig Cabral

David Brittain Bolen

Jeremy S Jarczyk

Peter C Kim

Sridhar Gopalam

Anuraag Shah

Fnu Manupriya

Systems and methods for managing conflicting background tasks in a dispersed storage network are provided. In embodiments, a method includes: gathering scheduled future task data for scheduled future tasks from a plurality of task scheduling modules within a dispersed storage network, wherein the scheduled future tasks are tasks associated with stored data objects; monitoring the scheduled future task data for scheduling conflicts based on stored rules; determining that a scheduling conflict exists between a first future task of the scheduled future tasks and a second future task of the scheduled future tasks; issuing instructions to at least one of the plurality of task scheduling modules to update the first future task or the second future task based on the scheduling conflict; and updating, by the at least one of the plurality of task scheduling modules, the first future task or the second future task based on the instructions.

Managing dispersed storage network background tasks

A method for execution by a dispersed storage and task (DST) processing unit includes generating contention level data by evaluating an update contention level in response to determining to update an entry of a node of a dispersed hierarchical index. The update of the node is executed when the contention level data indicates that the update contention level is favorable. An index update request is generated for transmission to an index update unit via a network when the contention level data indicates that the update contention level is unfavorable.

Utilizing a hierarchical index in a dispersed storage network

A method includes determining, by a computing device, to change a node of a hierarchical index structure. The method further includes determining, by the computing device, whether one or more other computing devices are attempting to change the node. The method further includes, when yes, determining, by the computing device and/or the other computing device(s), to use a delegate device to process multiple change requests to the node. The method further includes, when determined to use the delegate device, sending, by the computing device, a message to the delegate device requesting the delegate device to process the change to the node. The method further includes coordinating, by the delegate device, requested changes to the node by the computing device and the other computing device(s). The method further includes updating, by the delegate device, the node in accordance with the coordinating of the requested changes.

Coordinating node modification of an index structure via delegates

A method includes identifying, by a computing device of a dispersed storage network (DSN), a delegate device of a plurality of delegate devices of the DSN for processing a change to a node of a plurality of nodes of a hierarchical index structure. The method further includes sending, by the computing device, a change type specific request to the delegate device regarding the change to the node. The method further includes determining, by the delegate device, whether the delegate device is responsible for executing the change type specific request. When the delegate device is responsible for executing the change type specific request, the method further includes sending, by the delegate device, a response message to the computing device indicating that the delegate device is responsible for executing the change type specific request. The method further includes executing, by the delegate device, the change type specific request.

Engaging a delegate for modification of an index structure

A method for execution by one or more processing modules of one or more computing devices of a dispersed storage network (DSN), the method begins by, receiving a write data object request and writing and committing the data object as a set of encoded data slices into DSN memory. The method continues by writing and committing an index consistency write-intent to DSN memory. The method continues by writing metadata of the data object to DSN memory. The method continues by write and committing an index entry to DSN memory. The method continues, during a finalization of the index consistency write-intent, by executing the index consistency write-intent to ensure consistency between the metadata of the data object and metadata located in the index entry.

Ensuring metadata and index consistency using write intents

A method includes determining that a primary delegate device is unavailable. The method continues by identifying a fallback delegate device for changing a node of a hierarchical index structure using a deterministic function. The deterministic function includes performing a first modification of global namespace address of the unavailable primary delegate device to produce a first modified address identifier. The deterministic function further includes determining whether another delegate device of the plurality of delegate devices has a global namespace address corresponding to the first modified address identifier. When the global namespace address of other delegate device corresponds to the first modified address identifier, the method further includes processing a change to a node of the one or more nodes via the other delegate device as the fallback delegate device.

Fallback delegates for modification of an index structure

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Schaumburg, IL, United States of America

Tyler K Reid