Abstract: According to one embodiment of the present invention, a method for protecting authenticated communication in dynamic federated environments is provided. The method includes distributing shares of a private signature key to a group of users. When switching from an existing to a new group of users, the method includes producing a plurality of sub-shares from each of the distributed shares of existing users, with each sub-share being accompanied by a corresponding validity proof. The sub-shares from multiple existing users are combined to generate a set of shares for new users, with each new share being derived from sub-shares from multiple existing users.

Abstract: A scheduler selects an I/O from a session of a pool and updates token buckets associated with resource limits and reserves for the session and the pool and statistics used in determining fair sharing. To select an I/O, the scheduler identifies sessions with a non-empty queue, identifies head I/Os in the queues, computes for the head I/O a deadline using session and pool reserve buckets and a release time using session and pool limit buckets, and selects a head I/O with an earliest deadline that is past the release time. If the deadline of the selected candidate head I/O is in the past, the scheduler transfers the selected head I/O to the tail of the storage device queue. Otherwise, the scheduler selects the pool with the least amount of I/O traffic according to a session fair share estimator.

Abstract: A fault-tolerant and efficient way of deducing a set of inconsistent stripes for a network RAID protocol, wherein clients forward input/output (I/O) to a particular controller device called the coordinator, which executes RAID logic and which sends out device IOs to the relevant storage devices. If the coordinator fails then a new coordinator reconstructs its state from the storage devices.

Abstract: A resource management system uses a virtual resource pool distributed across a set of storage devices to manage resources in a distributed storage system. The storage devices dedicate a resource in an allocation pool available to the virtual resource pool. The virtual resource pool is a virtual storage server in which an application receives at least a predetermined amount of storage capacity, a predetermined level of performance, or a predetermined reliability, represented by tokens. A virtual resource pool manager gives the tokens to an application. The application transmits the tokens along with the commands to the storage device. The token represents a right to consume up to some limit of resources on a specific storage device in a computing session. The storage device locally tracks resource consumption through the token.

Abstract: According to one embodiment of the present invention, a method for protecting authenticated communication in dynamic federated environments is provided. The method includes distributing shares of a private signature key to a group of users. When switching from an existing to a new group of users, the method includes producing a plurality of sub-shares from each of the distributed shares of existing users, with each sub-share being accompanied by a corresponding validity proof. The sub-shares from multiple existing users are combined to generate a set of shares for new users, with each new share being derived from sub-shares from multiple existing users.

Abstract: A fault-tolerant and efficient way of deducing a set of inconsistent stripes for a network RAID protocol, wherein clients forward input/output (I/O) to a particular controller device called the coordinator, which executes RAID logic and which sends out device IOs to the relevant storage devices. If the coordinator fails then a new coordinator reconstructs its state from the storage devices.

Abstract: A fault-tolerant and efficient way of deducing a set of inconsistent stripes for a network RAID protocol, wherein clients forward input/output (I/O) to a particular controller device called the coordinator, which executes RAID logic and which sends out device IOs to the relevant storage devices. If the coordinator fails then a new coordinator reconstructs its state from the storage devices.

Abstract: A client node of a distributed storage system adaptive determines on an operation-by-operation basis whether to process a network-RAID IO operation (IO request) locally at the client node or to forward the IO request to a storage server of the system for processing. The client node determines to process the requested network-RAID operation at the client node when a local estimator for a type of the requested network-RAID operation is less than a central estimator for the type of the requested network-RAID operation. Otherwise, the client node determines to process the requested network-RAID operation at a storage server when the local estimator for the type of the requested network-RAID operation is greater than the central estimator for the type of the requested network-RAID operation.

Abstract: A RAID-configured grouped-object storage system provides reduced storage space overhead for small objects. The storage system includes a plurality stripes arranged across a plurality of physical objects. Each stripe includes a plurality of storage blocks that are each mapped on to a respectively different physical object. The storage system also includes a plurality of virtual objects each containing at least one storage block. A group of virtual objects is formed when a virtual object contains less storage blocks than the number of stripes by associating the virtual object with at least one virtual object containing less storage blocks than the number of stripes and/or at least one storage block containing zero values so that the storage blocks of each group of virtual objects equals the number of stripes. The storage blocks of each virtual object and of each group of virtual objects are mapped to a respectively different stripe.

Abstract: A data storage system is provided in which a migration plan generates migration plans for reaching a goal configuration from an initial configuration in a predetermined period of time. The migration plan initially makes terminal moves until no further terminal moves can be made. A shunt move is then made based on reducing the contention (the total size of the data stores that need to be moved onto a particular data stores device divided by the amount of excess capacity on the data storage device). The shunt is selected to lead to the lowest contention for the data storage system. Subsequently, the migration plan returns to making terminal moves to develop a migration plan. By determining existence and utilization dependencies of the various moves, independent moves are determined to be implemented in parallel with moves having dependencies. This produces parallelized migration plans which run much faster than sequential migration plans.

Abstract: A distributed data storage system is provided with a mechanism for determining data storage resource availability during data system failures. When a partition occurs, a coordinator requests all reachable replicas to begin a new epoch and each replica responds with its most recent epoch number and the list of replicas that it believes were active in that epoch. From the responses, the coordinator finds the maximum epoch number and the list of replicas in that epoch is taken as the list from which a quorum must be drawn. The coordinator establishes a quorum when, for each byte in the virtual store, the coordinator receives responses from more than half of the replicas for that byte. The coordinator then determines resource availability and sends out a message to all the reachable replicas with a new epoch number greater than the previous epoch number and the list of replicas active in this new epoch. The replicas receive this message, record the epoch number and the list of replicas, and proceed.

Abstract: A data storage system is provided in which a migration plan generates migration plans for reaching a goal configuration from an initial configuration in a predetermined period of time. The migration plan initially makes terminal moves until no further terminal moves can be made. A shunt move is then made based on reducing the contention (the total size of the data stores that need to be moved onto a particular data stores device divided by the amount of excess capacity on the data storage device). The shunt is selected to lead to the lowest contention for the data storage system. Subsequently, the migration plan returns to making terminal moves to develop a migration plan. Further migration plans are provided.