Microsoft Technology Licensing, LLC

Daniel Chan

Neal Robert Christiansen

Sarosh Cyrus Havewala

Craig Ashley Barkhouse

John D Slingwine

Karan Mehra

Surendra Verma

Shiv Kumar Rajpal

Matt Garson

Rajsekhar Das

Andrew M Herron

Malcolm James Smith

Juan-Lee Pang

Lane Haury

Kiran Kumar G Bangalore

Thiago Sigrist

A thinly provisioned storage system detects whether physical storage capacity is available when there is a request to allocate storage capacity, prior to data being written to the storage system. In particular, at the time when the file system allocates storage, such as when creating a file or performing an extending write (append) operation, allocating storage to an unallocated region of a sparse file, defragmenting a file, and the like, a storage system can verify that actual physical storage capacity is available. Thus, if there is insufficient actual physical capacity at the time when a storage allocation is attempted, then an error message can be sent and remedial action can be taken.

Managing capacity of a thinly provisioned storage system

A file system that operates on an underlying volume that has multiple tiers, each tier including a particular trait set. Upon creating or otherwise identifying a file system namespace (such as a directory or file) that is in a volume or that is to be included within the volume, a storage trait set to be applied corresponding to the file system namespace is identified. Then, the storage trait set is compared against the trait sets for the multiple tiers to identify a tier into which to store the file system namespace. The file system namespace is then caused to be stored within the identified tier. Thus, the file system is provided with a volume that has multiple tiers (each having different trait sets) to choose from in storing files.

File system operation on multi-tiered volume

Processing for file system volume error detection and processing for resultant error correction are separated to support system availability and user satisfaction. File system volumes for storing data structures are proactively scanned while the volumes remain online to search for errors or corruptions thereon. Found errors are scheduled to be corrected, i.e., spot corrected, dependent on the severity of the identified errors, error correction scheduling and/or at the determination of a file system administrator and/or user, to assist in maintaining minimal user and file system impact. When spot correction is initialized, one file system volume at a time is taken offline for correction. Spot correction verifies prior logged corruptions for the offline volume, and if independently verified, attempts to correct the prior noted corruptions. Volumes are retained offline only for the time necessary to verify and attempt to correct prior noted volume corruptions.

Proactive error scan and isolated error correction

Perceived corruptions encountered on file system volumes, and which cannot be initially remedied online, are processed to verify whether they are true, existing volume data structure corruptions or, alternatively, false positives. Upon the verification of one or more of a volume's corruptions, error scanning is performed to check for, and attempt to remedy online, all the existing corruptions on the volume. Subsequent to error scanning processing, if one or more verified corruptions continue to exist on a file system volume, at file system boot up time spot corruption correction is performed to attempt to remedy the existing, verified corruptions on the volume. Spot corruption correction is performed to attempt to correct verified data structure corruptions on a volume of the file system while the volume is maintained offline for the time necessary to attempt to correct its prior identified corruptions.

File system resiliency management

Data structure errors, or corruptions, identified during, e.g., normal computing device system processing, file system processing or user access processing, are verified prior to the file system identifying the error for offline correction or notifying the user or system administrator a data structure error exists. Identified data structure corruptions are verified while the file system volumes are maintained online and otherwise accessible to other processing tasks and user access. Verified data structure corruptions are logged for further corrective processing. Data structure corruptions that cannot be verified, i.e., false positives, are not further processed and are not identified to file system administrators or users as corruptions, freeing the file system to concentrate on normal processing and true, verifiable errors.

Online fault verification in a file system

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Daniel Chan