Panasas, Inc.

Garth Gibson

Daniel Belov

Mark C Holland

James D Zelenka

Jason Kenneth Small

Marc Unangst

Joel Jacobson

Nabeel Mian

David F Nagle

A data storage system includes a storage device divided into a plurality of blocks for storing data for a plurality of volumes, and a processor to execute instructions for maintaining a block map corresponding to the data stored on the storage device. The storage system may be part of a storage system network. The block map stores reference data indicating which of the volumes reference which blocks on the storage device, and which blocks on the storage device are unallocated. The reference data may include, for groups of one or more blocks, a first value identifying the oldest volume in which the group of blocks was allocated and a second value identifying the newest volume in which the group of blocks was allocated. The volumes may include one or more snapshots.

Data storage systems, methods and networks having a snapshot efficient block map

Parallel reconstruction of file components following a failure of one or more of the storage devices is implemented in the context of a storage system that includes a plurality of storage devices for storing file components and a plurality of metadata managers. A storage device having one or more unrecoverable read errors requiring reconstruction is identified. A metadata manager which will serve as a scheduler, and a plurality of metadata managers which serve as a plurality of workers, are identified. The plurality of workers includes metadata managers other than the scheduler. A scheduler service running on the metadata manager identified as the scheduler is used to construct a list of file components from the storage device affected by the one or more unrecoverable read errors requiring reconstruction. The scheduler service assembles a work list corresponding to each of a plurality of the workers. The work list for each worker includes a subset of file components from the list requiring reconstruction. The scheduler service instructs each worker to reconstruct data contained in the subset of file components on the work list of said worker. In response to the instructions from the scheduler service, the plurality of workers operates in parallel to reconstruct the data contained in the file components requiring reconstruction.

Systems and methods for parallel reconstruction of files and objects

A data storage system where a RAID-X format is implemented at a file level includes storage devices, and one or more nodes that access files from the storage devices. N represents a maximum limit of failures beyond which reconstruction of a file stored using the file level implementation is not possible. A directory is encoded for each of a plurality of files, and a map is encoded that includes a list of storage devices where components of the directory associated with the map reside. The encoding of the directory is performed using a RAID-X format that can tolerate at least N+1 failures prior to being unable to reconstruct the directory.

Methods for storing data in a data storage system where a RAID-X format or formats are implemented at a file level

A system includes storage devices where a RAID-X format is implemented at a file level. In response to a failure, a map is retrieved. The map includes a list of devices where components of at least one file reside. The map is used to determine whether a number of lost or damaged components associated with the file exceed a maximum limit beyond which reconstruction of a file stored using the file level implementation of the RAID-X format is not possible. If the maximum limit has not been exceeded, the file is reconstructed. The system continues to service data storage and access requests, with reconstruction being performed as a background operation, after a number of device failures has occurred which would have exceeded the maximum limit of device failures for reconstruction had the file been stored using a volume level implementation of the RAID-X format.

Systems and methods for facilitating file reconstruction and restoration in data storage systems where a RAID-X format is implemented at a file level within a plurality of storage devices

A hybrid quorum/consensus and primary-backup fault-tolerance model in an object-based distributed data storage system. When a primary manager fails, a hierarchy of network entities is established in which a group of realm managers first authorizes a failure-handling event through quorum/consensus and a backup manager (for the failing primary manager) then executes the decision of the quorum of realm managers. The realm managers, operating by consensus, determine whether (a) the primary manager can indeed be asserted to be down, and (b) whether there is a quorum of realm managers in agreement on this decision. If both are true, a master realm manager instructs the backup manager to proceed to execute the necessary steps to become the primary manager and function as the primary until the original primary manager is brought back into service. The hybrid fault-tolerance approach handles both single unit failures and network partitions in a unified way, without creating a single cluster out of the fault domain.

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Pittsburgh, PA, United States of America

Garth Gibson