Patent US5911779A successfully refreshed from Google Patents.
US5911779A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Storage device array architecture with copyback cache
Assignee: EMC Corp
•
Filing: 1997-03-31
•
Granted: 1999-06-15
•
Expires: 2017-03-31
Abstract
Abstract A fault-tolerant storage device array using a copyback cache storage unit for temporary storage. When a Write occurs to the RAID system, the data is immediately written to the first available location in the copyback cache storage unit. Upon completion of the Write to the copyback cache storage unit, the host CPU is immediately informed that the Write was successful. Thereafter, further storage unit accesses by the CPU can continue without waiting for an error-correction block update for the data just written. In a first embodiment of the invention, Read-Modify-Write operations are performed during idle time. In a second embodiment of the invention, normal Read-Modify-Write operation by the RAID system controller continue use Write data in the controller's buffer memory. In a third embodiment, at least two controllers, each associated with one copyback cache storage unit, copy Write data from controller buffers to the associated copyback cache storage unit. If a copyback cache storage unit fails, more than one controller share a single copyback storage unit. In a fourth embodiment, Write data is copied from a controller buffer to a reserved area of each storage unit comprising the array.
Inventors
- 👤 David C. Stallmo
- 👤 William A. Brant
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 20:12
CPC Classifications
G; G06; G06F; G06F11/00; G06F11/07; G06F11/16; G06F11/1666; G06F11/08; G06F11/10; G06F11/1076; G06F11/14; G06F11/1402; G06F11/1415; G06F11/1435; G06F11/20; G06F11/2053; G06F11/2056; G06F11/2087; G06F11/2094; G06F12/00; G06F12/02; G06F12/08; G06F12/0802; G06F12/0804; G11; G11B; G11B20/00; G11B20/10; G11B20/18; G11B20/1833; G06F11/1441; G06F11/2089; G06F12/0866; G06F2211/00; G06F2211/10; G06F2211/1002; G06F2211/1019; G06F2211/1059
Claims Analysis
Total Claims: 31
Claim 1
Independent Claim
202 words
A fault-tolerant storage device array including: a. a plurality of failure independent storage units for storing information as stripes of blocks, including at least data blocks and associated error-correction blocks; b. at least one copyback cache storage unit for temporarily storing data blocks; and c. a storage unit controller, coupled to the plurality of storage units and to the at least one copyback cache storage unit, including control means for: (1) writing received data blocks initially onto the at least one copyback cache storage unit as pending data blocks; (2) during idle time of at least some of the plurality of storage units: (a) reading at least one pending data block from at least one copyback cache storage unit; (b) accessing the storage units and reading information corresponding to each read pending data block; (c) generating an associated error-correction block from the read information and each read pending data block; and (d) writing each such read pending data block and associated error-correction block to a corresponding stripe of the idle storage units; and (3) acknowledging completion of writing each received data block to the at least one copyback cache storage unit before writing such data block to one of the storage units.
Claim 2
Dependent Claim
202 words
A fault-tolerant storage device array including: a. a plurality of failure independent storage units for storing information as stripes of blocks, including at least data blocks and associated error-correction blocks; b. at least one copyback cache storage unit for temporarily storing data blocks; and c. a storage unit controller, coupled to the plurality of storage units and to the at least one copyback cache storage unit, including control means for: (1) writing received data blocks initially onto the at least one copyback cache storage unit as pending data blocks; (2) during idle time of at least some of the plurality of storage units: (a) reading at least one pending data block from at least one copyback cache storage unit; (b) accessing the storage units and reading information corresponding to each read pending data block; (c) generating an associated error-correction block from the read information and each read pending data block; and (d) writing each such read pending data block and associated error-correction block to a corresponding stripe of the idle storage units; and (3) acknowledging completion of writing each received data block to the at least one copyback cache storage unit before writing such data block to one of the storage units.
Claim 3
Dependent Claim
37 words
The storage device array of claim 1, wherein the information corresponding to each read pending data block includes a corresponding old error-correction block and corresponding old data block read from the corresponding stripe of idle storage units.
Claim 4
Dependent Claim
70 words
The storage device array of claim 1, wherein generating an error-correction block further includes: a. reading a corresponding old data block from the corresponding stripe of the idle storage units; b. reading a corresponding old error-correction block from the corresponding stripe of the idle storage units; and c. exclusively-ORing the old data block, the old error correction block and the read pending data block, thereby generating a new error-correction block.
Claim 5
Dependent Claim
18 words
The fault-tolerant storage device array of claim 1, wherein at least one copyback cache storage unit is non-volatile.
Claim 6
Dependent Claim
186 words
A fault-tolerant storage device array including: a. a plurality of failure independent storage units for storing information as stripes of blocks, including at least data blocks and associated error-correction blocks; b. at least one copyback cache storage unit for temporarily storing data blocks, at least one of said at least one copyback cache storage unit being non-volatile; and c. a storage unit controller, coupled to the plurality of storage units and to the at least one copyback cache storage unit, including control means for: (1) writing received data blocks initially onto the at least one copyback cache storage unit as pending data blocks; (2) during idle time of at least some of the plurality of storage units: (a) reading at least one pending data block from at least one copyback cache storage unit; (b) accessing the storage units and reading information corresponding to each read pending data block; (c) generating an associated error-correction block from the read information and each read pending data block; and (d) writing each such read pending data block and associated error-correction block to a corresponding stripe of the idle storage units.
Claim 7
Dependent Claim
186 words
A fault-tolerant storage device array including: a. a plurality of failure independent storage units for storing information as stripes of blocks, including at least data blocks and associated error-correction blocks; b. at least one copyback cache storage unit for temporarily storing data blocks, at least one of said at least one copyback cache storage unit being non-volatile; and c. a storage unit controller, coupled to the plurality of storage units and to the at least one copyback cache storage unit, including control means for: (1) writing received data blocks initially onto the at least one copyback cache storage unit as pending data blocks; (2) during idle time of at least some of the plurality of storage units: (a) reading at least one pending data block from at least one copyback cache storage unit; (b) accessing the storage units and reading information corresponding to each read pending data block; (c) generating an associated error-correction block from the read information and each read pending data block; and (d) writing each such read pending data block and associated error-correction block to a corresponding stripe of the idle storage units.
Claim 8
Dependent Claim
39 words
The storage device array of claim 5, wherein the control means acknowledges completion of writing each received data block to the at least one copyback cache storage unit before writing such data block to one of the storage units.
Claim 9
Dependent Claim
37 words
The storage device array of claim 6, wherein the information corresponding to each read pending data block includes a corresponding old error-correction block and corresponding old data block read from the corresponding stripe of idle storage units.
Claim 10
Dependent Claim
70 words
The storage device array of claim 7, wherein generating an error-correction block further includes: a. reading a corresponding old data block from the corresponding stripe of the idle storage units; b. reading a corresponding old error-correction block from the corresponding stripe of the idle storage units; and c. exclusively-ORing the old data block, the old error correction block and the read pending data block, thereby generating a new error-correction block.
Claim 11
Dependent Claim
216 words
A fault-tolerant storage device array including: a. a plurality of failure independent storage units for storing information as stripes of blocks, including at least data blocks and associated error-correction blocks; b. at least one copyback cache storage unit for temporarily storing data blocks, at least one of said at least one copyback cache storage unit being non-volatile; and c. a storage unit controller, coupled to the plurality of storage units and to the at least one copyback cache storage unit, including control means for: (1) writing received data blocks initially onto the at least one copyback cache storage unit as pending data blocks; (2) during idle time of at least some of the plurality of storage units: (a) reading at least one pending data block from at least one copyback cache storage unit; (b) accessing the storage units and reading information corresponding to each read pending data block; (c) generating an associated error-correction block from the read information and each read pending data block; and (d) writing each such read pending data block and associated error-correction block to a corresponding stripe of the idle storage units; and (3) acknowledging completion of writing each received data block to the at least one copyback cache storage unit before writing such data block to one of the storage units.
Claim 12
Dependent Claim
216 words
A fault-tolerant storage device array including: a. a plurality of failure independent storage units for storing information as stripes of blocks, including at least data blocks and associated error-correction blocks; b. at least one copyback cache storage unit for temporarily storing data blocks, at least one of said at least one copyback cache storage unit being non-volatile; and c. a storage unit controller, coupled to the plurality of storage units and to the at least one copyback cache storage unit, including control means for: (1) writing received data blocks initially onto the at least one copyback cache storage unit as pending data blocks; (2) during idle time of at least some of the plurality of storage units: (a) reading at least one pending data block from at least one copyback cache storage unit; (b) accessing the storage units and reading information corresponding to each read pending data block; (c) generating an associated error-correction block from the read information and each read pending data block; and (d) writing each such read pending data block and associated error-correction block to a corresponding stripe of the idle storage units; and (3) acknowledging completion of writing each received data block to the at least one copyback cache storage unit before writing such data block to one of the storage units.
Claim 13
Dependent Claim
37 words
The storage device array of claim 9, wherein the information corresponding to each read pending data block includes a corresponding old error-correction block and corresponding old data block read from the corresponding stripe of idle storage units.
Claim 14
Dependent Claim
70 words
The storage device array of claim 9, wherein generating an error-correction block further includes: a. reading a corresponding old data block from the corresponding stripe of the idle storage units; b. reading a corresponding old error-correction block from the corresponding stripe of the idle storage units; and c. exclusively-ORing the old data block, the old error correction block and the read pending data block, thereby generating a new error-correction block.
Claim 15
Dependent Claim
186 words
A fault-tolerant storage device array including: a. a plurality of failure independent storage units for storing information as stripes of blocks, including at least data blocks and associated error-correction blocks; b. at least one copyback cache storage unit for temporarily storing data blocks; and c. a storage unit controller, coupled to the plurality of storage units and to the at least one copyback cache storage unit, including control means for: (1) writing received data blocks initially onto the at least one copyback cache storage unit as pending data blocks; (2) reading at least one pending data block from at least one copyback cache storage unit; (3) accessing the storage units and reading information corresponding to each read pending data block; (4) generating an associated error-correction block from the read information and each read pending data block; (5) writing each such read pending data block and associated error-correction block to a corresponding stripe of the storage units; and (6) acknowledging completion of writing each received data block to the at least one copyback cache storage unit before writing such data block to one of the storage units.
Claim 16
Dependent Claim
186 words
A fault-tolerant storage device array including: a. a plurality of failure independent storage units for storing information as stripes of blocks, including at least data blocks and associated error-correction blocks; b. at least one copyback cache storage unit for temporarily storing data blocks; and c. a storage unit controller, coupled to the plurality of storage units and to the at least one copyback cache storage unit, including control means for: (1) writing received data blocks initially onto the at least one copyback cache storage unit as pending data blocks; (2) reading at least one pending data block from at least one copyback cache storage unit; (3) accessing the storage units and reading information corresponding to each read pending data block; (4) generating an associated error-correction block from the read information and each read pending data block; (5) writing each such read pending data block and associated error-correction block to a corresponding stripe of the storage units; and (6) acknowledging completion of writing each received data block to the at least one copyback cache storage unit before writing such data block to one of the storage units.
Claim 17
Dependent Claim
37 words
The storage device array of claim 12, wherein the information corresponding to each read pending data block includes a corresponding old error-correction block and corresponding old data block read from the corresponding stripe of the storage units.
Claim 18
Dependent Claim
68 words
The storage device array of claim 12, wherein generating an error-correction block further includes: a. reading a corresponding old data block from the corresponding stripe of the storage units; b. reading a corresponding old error-correction block from the corresponding stripe of the storage units; and c. exclusively-ORing the old data block, the old error correction block and the read pending data block, thereby generating a new error-correction block.
Claim 19
Dependent Claim
17 words
The storage device array of claim 12, wherein at least one copyback cache storage unit is non-volatile.
Claim 20
Dependent Claim
51 words
The storage device array of claim 12, wherein said storage unit controller further includes control means for reading requested data blocks from at least one copyback cache storage unit when such requested data blocks have not been written to the plurality of storage units, otherwise from the plurality of storage units.
Claim 21
Dependent Claim
171 words
A fault-tolerant storage device array including: a. a plurality of failure independent storage units for storing information as stripes of blocks, including at least data blocks and associated error-correction blocks; b. at least one copyback cache storage unit for temporarily storing data blocks, at least one of said at least one copyback cache storage unit being non-volatile; and c. a storage unit controller, coupled to the plurality of storage units and to the at least one copyback cache storage unit, including control means for: (1) writing received data blocks initially onto the at least one copyback cache storage unit as pending data blocks; (2) reading at least one pending data block from at least one copyback cache storage unit; (3) accessing the storage units and reading information corresponding to each read pending data block; (4) generating an associated error-correction block from the read information and each read pending data block; and (5) writing each such read pending data block and associated error-correction block to a corresponding stripe of the storage units.
Claim 22
Dependent Claim
171 words
A fault-tolerant storage device array including: a. a plurality of failure independent storage units for storing information as stripes of blocks, including at least data blocks and associated error-correction blocks; b. at least one copyback cache storage unit for temporarily storing data blocks, at least one of said at least one copyback cache storage unit being non-volatile; and c. a storage unit controller, coupled to the plurality of storage units and to the at least one copyback cache storage unit, including control means for: (1) writing received data blocks initially onto the at least one copyback cache storage unit as pending data blocks; (2) reading at least one pending data block from at least one copyback cache storage unit; (3) accessing the storage units and reading information corresponding to each read pending data block; (4) generating an associated error-correction block from the read information and each read pending data block; and (5) writing each such read pending data block and associated error-correction block to a corresponding stripe of the storage units.
Claim 23
Dependent Claim
39 words
The storage device array of claim 17, wherein the control means acknowledges completion of writing each received data block to the at least one copyback cache storage unit before writing such data block to one of the storage units.
Claim 24
Dependent Claim
37 words
The storage device array of claim 18, wherein the information corresponding to each read pending data block includes a corresponding old error-correction block and corresponding old data block read from the corresponding stripe of the storage units.
Claim 25
Dependent Claim
68 words
The storage device array of claim 19, wherein generating an error-correction block further includes: a. reading a corresponding old data block from the corresponding stripe of the storage units; b. reading a corresponding old error-correction block from the corresponding stripe of the storage units; and c. exclusively-ORing the old data block, the old error correction block and the read pending data block, thereby generating a new error-correction block.
Claim 26
Dependent Claim
51 words
The storage device array of claim 17, wherein said storage unit controller further includes control means for reading requested data blocks from at least one copyback cache storage unit when such requested data blocks have not been written to the plurality of storage units, otherwise from the plurality of storage units.
Claim 27
Dependent Claim
200 words
A fault-tolerant storage device array including: a. a plurality of failure independent storage units for storing information as stripes of blocks, including at least data blocks and associated error-correction blocks; b. at least one copyback cache storage unit for temporarily storing data blocks, at least one of said at least one copyback cache storage unit being non-volatile; and c. a storage unit controller, coupled to the plurality of storage units and to the at least one copyback cache storage unit, including control means for: (1) writing received data blocks initially onto the at least one copyback cache storage unit as pending data blocks; (2) reading at least one pending data block from at least one copyback cache storage unit; (3) accessing the storage units and reading information corresponding to each read pending data block; (4) generating an associated error-correction block from the read information and each read pending data block; (5) writing each such read pending data block and associated error-correction block to a corresponding stripe of the storage units; and (6) acknowledging completion of writing each received data block to the at least one copyback cache storage unit before writing such data block to one of the storage units.
Claim 28
Dependent Claim
200 words
A fault-tolerant storage device array including: a. a plurality of failure independent storage units for storing information as stripes of blocks, including at least data blocks and associated error-correction blocks; b. at least one copyback cache storage unit for temporarily storing data blocks, at least one of said at least one copyback cache storage unit being non-volatile; and c. a storage unit controller, coupled to the plurality of storage units and to the at least one copyback cache storage unit, including control means for: (1) writing received data blocks initially onto the at least one copyback cache storage unit as pending data blocks; (2) reading at least one pending data block from at least one copyback cache storage unit; (3) accessing the storage units and reading information corresponding to each read pending data block; (4) generating an associated error-correction block from the read information and each read pending data block; (5) writing each such read pending data block and associated error-correction block to a corresponding stripe of the storage units; and (6) acknowledging completion of writing each received data block to the at least one copyback cache storage unit before writing such data block to one of the storage units.
Claim 29
Dependent Claim
37 words
The storage device array of claim 22, wherein the information corresponding to each read pending data block includes a corresponding old error-correction block and corresponding old data block read from the corresponding stripe of the storage units.
Claim 30
Dependent Claim
68 words
The storage device array of claim 22, wherein generating an error-correction block further includes: a. reading a corresponding old data block from the corresponding stripe of the storage units; b. reading a corresponding old error-correction block from the corresponding stripe of the storage units; and c. exclusively-ORing the old data block, the old error correction block and the read pending data block, thereby generating a new error-correction block.
Claim 31
Dependent Claim
51 words
The storage device array of claim 22, wherein said storage unit controller further includes control means for reading requested data blocks from at least one copyback cache storage unit when such requested data blocks have not been written to the plurality of storage units, otherwise from the plurality of storage units.
References Cited (Backward Citations)
US3893178A
Cited
US4092732A
Cited
US4467421A
Cited
US4430701A
Cited
US4562576A
Cited
US4593354A
Cited
JPS59153251A
Cited
US4604750A
Cited
US4817035A
Cited
US4849929A
Cited
US4667326A
Cited
US4754397A
Cited
US4768193A
Cited
JPS62110902A
Cited
US4733396A
Cited
US4958351A
Cited
US4722085A
Cited
US4761785A
Cited
US4761785B1
Cited
US4791642A
Cited
US4775978A
Cited
US4870643A
Cited
US4899342A
Cited
WO1989009468A1
Cited
US4993030A
Cited
US4920539A
Cited
US4914656A
Cited
US4995041A
Cited
EP0416968A2
Cited
US5058116A
Cited
US5185876A
Cited
US5274799A
Cited
US5341381A
Cited
US5398253A
Cited
US5548711A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2002-06-14 | 2002-12-14 | 2003-06-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2006-06-14 | 2006-12-14 | 2007-06-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2010-06-14 | 2010-12-14 | 2011-06-15 | $7700.00 | Window Closed / Lapsed |