Google Inc.

Panasas, Inc.

Marc Unangst

Garth Gibson

Michael De Rosa

David F Nagle

Methods and apparatuses for dynamically adjusting sampling rates for statistical data collection are taught. Records associated with a first task communicating with a second task that are sampled at a first sampling rate are received. At least the first task is associated with a first processing job. A target sampling rate for the first processing job is determined using the records where the target sampling rate is based on a minimum sampling quota and a maximum sampling quota. The target sampling rate is compared to the first sampling rate, and a determination of whether to adjust the first sampling rate to the target sampling rate is based on a result of the comparison. In this manner, tracing of processing jobs, such as those including a plurality of tasks, can be adjusted based on the needs and size of the job and network limitations.

Dynamic sampling rate adjustment for rate-limited statistical data collection

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

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Pittsburgh, PA, United States of America

Marc Unangst