US5717850A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Efficient system for predicting and processing storage subsystem failure
Assignee: International Business Machines Corp
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Filing: 1996-03-12
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Granted: 1998-02-10
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Expires: 2016-03-12
Abstract
Abstract Predictive failure analysis of a storage subsystem is efficiently conducted and data quickly recovered from a failed Read operation. This may be implemented in a storage system including a host coupled to a supervising processor that couples to a parity-equipped RAID storage subsystem having multiple HDAs each including an HDA controller and at least one storage medium. In one embodiment, when an HDA experiences an error during a Read attempt, the HDA transmits a recovery alert signal to the supervising processor; then, the processor and HDA begin remote and local recovery processes in parallel. The first process to complete provides the data to the host, and the second process is aborted. In another embodiment, an HDA's PFA operations are restricted to idle times of the HDA. A different embodiment limits HDA performance of PFA to times when the processor is conducting data reconstruction. Another embodiment monitors HDA errors at the supervisory processor level, initiating an HDA's PFA operations when errors at that HDA have a certain characteristic, such as a predetermined frequency of occurrence.
Inventors
- 👤 Norman Apperley
- 👤 James Thomas Brady
- 👤 Steven Gerdt
- 👤 Alden B. Johnson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 07:19
CPC Classifications
G; G06; G06F; G06F11/00; G06F11/07; G06F11/16; G06F11/20; G06F11/2053; G06F11/2094; G06F11/008; G06F11/08; G06F11/10; G06F11/1076; G06F11/1088
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
221 words
A method for data recovery in a storage system including a supervising processor coupled to a parity-equipped RAID storage subsystem having multiple head disk assemblies ("HDA") each HDA including an HDA controller and at least one storage medium, said method comprising the steps of: the supervising processor receiving a Read request for reading target data; the supervising processor directing a first HDA to read the target data; the first HDA attempting to read the target data and detecting a data error during the attempt; the first HDA transmitting a recovery alert signal indicative of the data error to the supervising processor; the first HDA initiating a retry process to provide an output of the target data; the supervising processor initiating a reconstruction process concurrently with the retry process to provide an output of the target data by combining supplementary data and stored parity, said supplementary data comprising data corresponding to the target data and stored elsewhere in the RAID storage subsystem than the first HDA, and said stored parity comprising parity corresponding to the target data and supplementary data and stored in the RAID storage subsystem; and determining which of the retry and reconstruction processes first completes; providing an output of target data from the first completing process in response to the read request; and aborting the process not completing first.
Claim 2
Independent Claim
221 words
A method for data recovery in a storage system including a supervising processor coupled to a parity-equipped RAID storage subsystem having multiple head disk assemblies ("HDA") each HDA including an HDA controller and at least one storage medium, said method comprising the steps of: the supervising processor receiving a Read request for reading target data; the supervising processor directing a first HDA to read the target data; the first HDA attempting to read the target data and detecting a data error during the attempt; the first HDA transmitting a recovery alert signal indicative of the data error to the supervising processor; the first HDA initiating a retry process to provide an output of the target data; the supervising processor initiating a reconstruction process concurrently with the retry process to provide an output of the target data by combining supplementary data and stored parity, said supplementary data comprising data corresponding to the target data and stored elsewhere in the RAID storage subsystem than the first HDA, and said stored parity comprising parity corresponding to the target data and supplementary data and stored in the RAID storage subsystem; and determining which of the retry and reconstruction processes first completes; providing an output of target data from the first completing process in response to the read request; and aborting the process not completing first.
Claim 3
Dependent Claim
22 words
The method of claim 1, the reconstruction process including steps of applying an exclusive-OR operation to the supplementary data and stored parity.
Claim 4
Dependent Claim
30 words
The method of claim 1, wherein the RAID storage subsystem includes a spare HDA, and the method further comprises a step of rebuilding the target data upon the spare HDA.
Claim 5
Dependent Claim
16 words
The method of claim 1, said at least one storage medium being a single storage medium.
Claim 6
Dependent Claim
15 words
The method of claim 1, said at least one storage medium comprising multiple storage media.
Claim 7
Dependent Claim
232 words
A program instructions storage medium tangibly embodying a machine-readable program of instructions to perform method steps for recovery in a storage system that includes a supervising processor coupled to a parity-equipped RAID storage subsystem having multiple head disk assemblies ("HDA") each including an HDA controller and at least one storage medium, said method steps comprising: the supervising processor receiving a Read request for reading target data; the supervising processor directing a first HDA to read the target data; the first HDA attempting to read the target data and detecting a data error during the attempt; the first HDA transmitting a recovery alert signal indicative of the data error to the supervising processor; the first HDA initiating a retry process to provide an output of the target data; the supervising processor initiating a reconstruction process concurrently with the retry process to provide an output of the target data by combining supplementary data and stored parity, said supplementary data comprising data corresponding to the target data and stored elsewhere in the RAID storage subsystem than the first HDA, and said stored parity comprising parity corresponding to the target data and supplementary data and stored in the RAID storage subsystem; and determining which of the retry and reconstruction processes first completes; providing an output of target data from the first completing process in response to the Read request; and aborting the process not completing first.
Claim 8
Dependent Claim
232 words
A program instructions storage medium tangibly embodying a machine-readable program of instructions to perform method steps for recovery in a storage system that includes a supervising processor coupled to a parity-equipped RAID storage subsystem having multiple head disk assemblies ("HDA") each including an HDA controller and at least one storage medium, said method steps comprising: the supervising processor receiving a Read request for reading target data; the supervising processor directing a first HDA to read the target data; the first HDA attempting to read the target data and detecting a data error during the attempt; the first HDA transmitting a recovery alert signal indicative of the data error to the supervising processor; the first HDA initiating a retry process to provide an output of the target data; the supervising processor initiating a reconstruction process concurrently with the retry process to provide an output of the target data by combining supplementary data and stored parity, said supplementary data comprising data corresponding to the target data and stored elsewhere in the RAID storage subsystem than the first HDA, and said stored parity comprising parity corresponding to the target data and supplementary data and stored in the RAID storage subsystem; and determining which of the retry and reconstruction processes first completes; providing an output of target data from the first completing process in response to the Read request; and aborting the process not completing first.
Claim 9
Dependent Claim
25 words
The program instructions storage medium of claim 6, the reconstruction process including steps of applying an exclusive-OR operation to the supplementary data and stored parity.
Claim 10
Dependent Claim
34 words
The program instructions storage medium of claim 6, wherein the RAID storage subsystem includes a spare HDA, and the method steps further comprise the steps of rebuilding the target data upon the spare HDA.
Claim 11
Dependent Claim
19 words
The program instructions storage medium of claim 6, said at least one storage medium being a single storage medium.
Claim 12
Dependent Claim
18 words
The program instructions storage medium of claim 6, said at least one storage medium comprising multiple storage media.
References Cited (Backward Citations)
US5333314A
Cited
US4989206A
Cited
US5148432A
Cited
US5088081A
Cited
US5124987A
Cited
US5263145A
Cited
US5220569A
Cited
US5347647A
Cited
US5357607A
Cited
US5261083A
Cited
US5239659A
Cited
US5257391A
Cited
US5313626A
Cited
US5371882A
Cited
US5359728A
Cited
US5270880A
Cited
US5608891A
Cited
US5386549A
Cited
US5623595A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2001-02-09 | 2001-08-11 | 2002-02-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-02-09 | 2005-08-11 | 2006-02-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-02-09 | 2009-08-11 | 2010-02-10 | $7700.00 | Window Closed / Lapsed |