US6654912B1
Expired / Lapsed
US
⏱️ 0.0 years remaining
Recovery of file system data in file servers mirrored file system volumes
Assignee: NetApp Inc
•
Filing: 2000-10-04
•
Granted: 2003-11-25
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Expires: 2020-10-04
Abstract
Abstract The invention provides a method and system for recovery of file system data in file servers having mirrored file system volumes. The invention makes use of a “snapshot” feature of a robust file system (the “WAFL File System”) disclosed in the Incorporated Disclosures, to rapidly determined which of two or more mirrored volumes is most up-to-date, and which file blocks of the most recent mirrored volume have been changed from each one of the mirrored file systems. In a preferred embodiment, among a plurality of mirrored volumes, the invention rapidly determines which is the most up-to-date by examining a consistency point number maintained by the WAFL File System at each mirrored volume. The invention rapidly pairwise determines what blocks are shared between that most up-to-date mirrored volume and each other mirrored volume, in response to a snapshot of the file system maintained at each mirrored volume and are stored in common pairwise between each mirrored volume and the most up-to-date mirrored volume. The invention re synchronizes only those blocks that have been changed between the common snapshot and the most up-to-date snapshot.
Inventors
- 👤 Srinivasan Viswanathan
- 👤 Steven R. Kleiman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 15:50
CPC Classifications
G; G06; G06F; G06F11/00; G06F11/07; G06F11/16; G06F11/20; G06F11/2053; G06F11/2056; G06F11/2082; G06F11/2064; G06F11/14; G06F11/1471; Y; Y10; Y10S; Y10S707/00; Y10S707/99951; Y10S707/99952; Y10S707/99953; Y10S707/99955
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
58 words
A method, including steps of examining a plurality of mirrored file system volumes for a consistency point value; determining a most up-to-date said file system volume in response to said steps of examining; and selecting a set of changed file blocks between said up-to-date said file system and each one of said plurality of mirrored file system volumes.
Claim 2
Independent Claim
58 words
A method, including steps of examining a plurality of mirrored file system volumes for a consistency point value; determining a most up-to-date said file system volume in response to said steps of examining; and selecting a set of changed file blocks between said up-to-date said file system and each one of said plurality of mirrored file system volumes.
Claim 3
Dependent Claim
58 words
A method as in claim 1 , wherein said steps of selecting include determining a snapshot held in common between said most up-to-date said file system volume and at least one of said plurality of mirrored file system volumes; and selecting those file blocks changed between said snapshot held in common and said up-to-date said file system volume.
Claim 4
Dependent Claim
31 words
A method as in claim 1 or 2 , including steps of re-synchronizing at least one of said plurality of mirrored file system volumes in response to said steps of selecting.
Claim 5
Dependent Claim
109 words
Apparatus including a plurality of mirrored file system volumes, each having at least one snapshot including an entire consistent file system, each said snapshot having a consistency point value; a first comparison element capable of being coupled to a plurality of said consistency point values; a second comparison element, responsive to an output of said first comparison element, said second comparison element being capable of being coupled (a) to a first snapshot associated with said output on a first said volume and (b) to a second snapshot associated with a second said volume, said second comparison element being capable of providing a selection of file blocks in response thereto.
Claim 6
Dependent Claim
109 words
Apparatus including a plurality of mirrored file system volumes, each having at least one snapshot including an entire consistent file system, each said snapshot having a consistency point value; a first comparison element capable of being coupled to a plurality of said consistency point values; a second comparison element, responsive to an output of said first comparison element, said second comparison element being capable of being coupled (a) to a first snapshot associated with said output on a first said volume and (b) to a second snapshot associated with a second said volume, said second comparison element being capable of providing a selection of file blocks in response thereto.
Claim 7
Dependent Claim
22 words
Apparatus as in claim 4 , wherein said second snapshot is held in common between said first volume and said second volume.
Claim 8
Dependent Claim
32 words
Apparatus as in claim 4 or 5 , including an element capable of re-synchronizing at least one of said plurality of mirrored file system volumes in response to said second comparison element.
References Cited (Backward Citations)
US4761785A
Cited
US4761785B1
Cited
US4897781A
Cited
US4875159A
Cited
US4937763A
Cited
US5067099A
Cited
US5163148A
Cited
US5355453A
Cited
US5276867A
Cited
EP0462917A2
Cited
US5208813A
Cited
US5357509A
Cited
US5235601A
Cited
EP0492808A2
Cited
EP0537098A2
Cited
US5313626A
Cited
EP0552580A2
Cited
US5305326A
Cited
US5335235A
Cited
WO1994029796A1
Cited
US5819292A
Cited
US5948110A
Cited
US5649196A
Cited
US5835953A
Cited
US5649152A
Cited
US5604862A
Cited
US5666353A
Cited
US5963962A
Cited
EP0767431A1
Cited
US5907672A
Cited
US5819310A
Cited
US6549921B1
Cited
US5996106A
Cited
US5873101A
Cited
US5996086A
Cited
US6101585A
Cited
US6212531B1
Cited
US6182198B1
Cited
WO1999066401A1
Cited
WO2000007104A1
Cited
US6119244A
Cited
US6397307B2
Cited
WO2001031446A1
Cited
WO2001043368A1
Cited
US6341341B1
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2006-11-24 | 2007-05-26 | 2007-11-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2010-11-24 | 2011-05-26 | 2011-11-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2014-11-24 | 2015-05-26 | 2015-11-25 | $7700.00 | Window Closed / Lapsed |