US6233696B1
Expired / Lapsed
US
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Data verification and repair in redundant storage systems
Assignee: EMC Corp
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Filing: 1997-12-31
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Granted: 2001-05-15
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Expires: 2017-12-31
Abstract
Abstract Method and apparatus for identifying data coherence problems in a storage system including redundant information are disclosed. A first copy of a data unit is compared with a generated copy of the data unit, to identify mismatched data. The redundant information may be parity information in a RAID architecture. The method and apparatus may repair data coherence problems.
Inventors
- 👤 Ishay Kedem
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 09:05
CPC Classifications
G; G06; G06F; G06F11/00; G06F11/07; G06F11/0703; G06F11/0706; G06F11/0727; G06F11/0751; G06F11/08; G06F11/10; G06F11/1076; G06F11/16; G06F11/20; G06F11/2053; G06F11/2056; G06F11/2082; G06F11/2087; G06F2211/00; G06F2211/10; G06F2211/1002; G06F2211/104
Claims Analysis
Total Claims: 35
Claim 1
Independent Claim
92 words
A method of diagnosing a data coherence problem in a storage system that includes a plurality of storage devices, each storing a data segment, the storage system storing redundant information corresponding to the data segments, the method comprising steps of: (a) providing a first copy of one of the data segments; (b) using the redundant information to generate a corresponding copy of the one data segment; and (c) comparing the first copy with the corresponding copy to determine when a data coherence problem exists between the first copy and the redundant information.
Claim 2
Independent Claim
92 words
A method of diagnosing a data coherence problem in a storage system that includes a plurality of storage devices, each storing a data segment, the storage system storing redundant information corresponding to the data segments, the method comprising steps of: (a) providing a first copy of one of the data segments; (b) using the redundant information to generate a corresponding copy of the one data segment; and (c) comparing the first copy with the corresponding copy to determine when a data coherence problem exists between the first copy and the redundant information.
Claim 3
Dependent Claim
16 words
The method of claim 1 , wherein the data segments are in a parity redundancy group.
Claim 4
Dependent Claim
20 words
The method of claim 1 , wherein the redundant information comprises parity data stored in one of the data segments.
Claim 5
Dependent Claim
38 words
The method of claim 1 , further comprising a step of: (d) when a data coherence problem is found at step (c), identifying which among the one data segment and the redundant information is not up to date.
Claim 6
Dependent Claim
32 words
The method of claim 4 , wherein the step (d) comprises a step of comparing a time stamp corresponding to the first copy with a time stamp corresponding to the corresponding copy.
Claim 7
Dependent Claim
26 words
The method of claim 4 , further comprising a step of repairing the one of the data segments and the redundant information identified in step (d).
Claim 8
Dependent Claim
28 words
The method of claim 1 , wherein each data segment is a track of data storing a plurality of data units, each data unit being a CKD record.
Claim 9
Dependent Claim
15 words
The method of claim 1 , wherein each data segment is a fixed size block.
Claim 10
Dependent Claim
29 words
The method of claim 1 , wherein each data segment is a track of data storing a plurality of data units, each data unit being a fixed size block.
Claim 11
Dependent Claim
53 words
The method of claim 1 , wherein: the data segements are in a redundancy group; and the steps (a), (b) and (c) are repeated for each data segment in the redundancy group that includes actual user data, independent of whether any potential data coherence problem is identified with respect to other data segments.
Claim 12
Dependent Claim
14 words
The method of claim 1 , wherein the first copy includes actual user data.
Claim 13
Dependent Claim
22 words
The method of claim 1 , further comprising a step (e) of determining whether the corresponding copy is a viable data segment.
Claim 14
Dependent Claim
16 words
The method of claim 12 , wherein the step (e) is performed before the step (c).
Claim 15
Dependent Claim
39 words
The method of claim 12 , wherein the step (e) comprises steps of: generating an error code for a data unit in the corresponding copy; and comparing the generated error code with an error code in the corresponding copy.
Claim 16
Dependent Claim
42 words
The method of claim 12 , wherein the step (e) comprises steps of: determining an expected value for a field in a data unit in the corresponding copy; and comparing the expected value with a stored value stored in the data unit.
Claim 17
Dependent Claim
15 words
The method of claim 15 , wherein the expected value is a logical block address.
Claim 18
Dependent Claim
37 words
The method of claim 12 , wherein the step (e) comprises a step of: (f) determining when a field of a data unit in the corresponding copy is within a range of expected values for the field.
Claim 19
Dependent Claim
19 words
The method of claim 17 , wherein the step (f) comprises a step of examining a time stamp field.
Claim 20
Dependent Claim
76 words
A storage system comprising: a plurality of storage devices, each storing a data segment, the data segments being in a redundancy group that includes redundant information; and a data coherence tester, coupled to the storage devices, to generate a corresponding copy of one data segment and to compare a first copy of the one data segment with the corresponding copy to determine when a data coherence problem exists between the first copy and the redundant information.
Claim 21
Dependent Claim
76 words
A storage system comprising: a plurality of storage devices, each storing a data segment, the data segments being in a redundancy group that includes redundant information; and a data coherence tester, coupled to the storage devices, to generate a corresponding copy of one data segment and to compare a first copy of the one data segment with the corresponding copy to determine when a data coherence problem exists between the first copy and the redundant information.
Claim 22
Dependent Claim
16 words
The storage system of claim 19 , wherein the redundancy group is a parity redundancy group.
Claim 23
Dependent Claim
38 words
The storage system of claim 20 , wherein the data coherence tester comprises means for identifying which among the one data segment and the redundant information is not up to date, when a data coherence problem is found.
Claim 24
Dependent Claim
33 words
The storage system of claim 21 , wherein the data coherence tester comprises means for comparing a time stamp corresponding to the first copy with a time stamp corresponding to the corresponding copy.
Claim 25
Dependent Claim
21 words
The storage system of claim 21 , further comprising means for repairing the data segment identified by the means for identifying.
Claim 26
Dependent Claim
45 words
The storage system of claim 20 , wherein the data coherence tester comprises: means for generating corresponding copies of each of the data segments that include actual user data, independent of whether any potential data coherence problem is identified with respect to other data segments.
Claim 27
Dependent Claim
15 words
The storage system of claim 20 , wherein the first copy includes actual user data.
Claim 28
Dependent Claim
25 words
The storage system of claim 20 , wherein the data coherence tester comprises means for determining whether the corresponding copy is a viable data segment.
Claim 29
Dependent Claim
43 words
The storage system of claim 26 , wherein the means for determining comprises: means for generating an error code for a data unit in the corresponding copy; and means for comparing the generated error code with an error code in the corresponding copy.
Claim 30
Dependent Claim
46 words
The storage system of claim 26 , wherein the means for determining comprises: means for determining an expected value for a field in a data unit in the corresponding copy; and means for comparing the expected value with a stored value stored in the data unit.
Claim 31
Dependent Claim
16 words
The storage system of claim 28 , wherein the expected value is a logical block address.
Claim 32
Dependent Claim
37 words
The storage system of claim 26 , wherein the means for determining comprises means for determining when a field of a data unit in the corresponding copy is within a range of expected values for the field.
Claim 33
Dependent Claim
24 words
The storage system of claim 30 , wherein the system means for determining when a field comprises means for examining a time stamp field.
Claim 34
Dependent Claim
83 words
A storage system comprising: a plurality of storage devices, each storing a data segment, the data segments of data being in a redundancy group that includes redundant information; means, coupled to the plurality of storage devices, for generating a corresponding copy of one data segment; and means, responsive to the means for generating, for comparing a first copy of the one data segment with the corresponding copy to determine when a data coherence problem exists between the first copy and the redundant information.
Claim 35
Dependent Claim
83 words
A storage system comprising: a plurality of storage devices, each storing a data segment, the data segments of data being in a redundancy group that includes redundant information; means, coupled to the plurality of storage devices, for generating a corresponding copy of one data segment; and means, responsive to the means for generating, for comparing a first copy of the one data segment with the corresponding copy to determine when a data coherence problem exists between the first copy and the redundant information.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2004-05-14 | 2004-11-13 | 2005-05-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2008-05-14 | 2008-11-13 | 2009-05-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2012-05-14 | 2012-11-13 | 2013-05-15 | $7700.00 | Window Closed / Lapsed |