Abstract: Selective repair of fragmentation in a synthetic backup, based at least in part on a dynamically-determined repair criteria, is disclosed. In various embodiments, a locality measure is computed with respect to a group of segments comprising a portion of a file. The computed locality measure is compared to an at least partly dynamically determined fragmentation repair criteria, and a repair decision is made based at least in part on the comparison.

Abstract: Fragmentation repair of synthetic backups is disclosed. In various embodiments, a locality measure is computed with respect to a group of segments comprising a portion of a file. The computed locality measure is compared to a repair criteria. A decision whether to repair fragmentation of segments comprising the group is made based at least in part on the comparison.

Abstract: Opportunistic repair of fragmentation in a synthetic backup is disclosed. In various embodiments, data generated to perform processing other than fragmentation repair is received. At least a portion of the received data is used to compute a locality measure with respect to a group of segments comprising a portion of a file. A decision whether to repair fragmentation of segments comprising the group is made based at least in part on the computed locality measure.

Abstract: Selective repair of fragmentation in a synthetic backup, based at least in part on a dynamically-determined repair criteria, is disclosed. In various embodiments, a locality measure is computed with respect to a group of segments comprising a portion of a file. The computed locality measure is compared to an at least partly dynamically determined fragmentation repair criteria, and a repair decision is made based at least in part on the comparison.

Abstract: Selective repair of fragmentation in a synthetic backup, based at least in part on a dynamically-determined repair criteria, is disclosed. In various embodiments, a locality measure is computed with respect to a group of segments comprising a portion of a file. The computed locality measure is compared to an at least partly dynamically determined fragmentation repair criteria, and a repair decision is made based at least in part on the comparison.

Abstract: Embodiments of this invention are directed to a system and method for characterizing and modeling a virtual synthetic file system workload. In one embodiment, a virtual synthetic system is adapted to select a first location in a prior generation dataset of a first cluster and generate a first offset using a distance distribution function. Thereafter, the virtual synthetic system selects a second location in the prior generation dataset of a second cluster, wherein the second location is offset from the first cluster by the first offset. Finally, the virtual synthetic system modifies each cluster selected on the prior generation dataset thereby creating a next generation dataset. This process is repeated to generate multiple generations of a dataset. Other embodiments are also described herein.

Abstract: A method for reading data from data storage is disclosed. A prefetch hint identifying a chunk of data a requesting node anticipates the requesting node will request that a controller retrieve from data storage is received. The prefetch hint is stored in a buffer at the controller. A determination that the prefetch hint is ready for processing is made. The determination is based at least in part on an offset or other data indicating a place of the chunk of data within a sequence of related chunks of data one or more of which may have been read previously into a cache of the controller. The prefetch hint is processed in response to determining that the prefetch hint is ready for processing, including by reading the chunk of data from a data storage of the controller and storing the chunk of data in the cache.

Abstract: The present invention provides a system and method for managing quality of service for a storage system that includes several file systems that share resources. The system may include a Quality of Service (QoS) manager and a request limitation process or “throttle” for limiting requests to the file systems based on measured operational data. The QoS manager employs various methods for managing quality of service including controlling memory usage of clean pages and other resources, admission control, and controlling the rate at which modified buffers are written to disk.

Abstract: A system and method for managing software upgrades in a distributed computing system. The distributed computing system may include a plurality of nodes which provide one or more fault-tolerant services. The system and method perform software upgrades in a sequential or “rolling” manner (e.g., node by node). The rolling upgrade process allows all services and data of the distributed computing system to remain operable and available throughout the upgrade process.

Abstract: A system and method for managing software upgrades in a distributed computing system. The distributed computing system may include a plurality of nodes which provide one or more fault-tolerant services. The system and method perform software upgrades in a sequential or “rolling” manner (e.g., node by node). The rolling upgrade process allows all services and data of the distributed computing system to remain operable and available throughout the upgrade process.