Prosecution Insights
Last updated: April 19, 2026
Application No. 18/333,494

Variable Redundancy For Metadata In Storage Systems

Non-Final OA §103
Filed
Jun 12, 2023
Examiner
CARDWELL, ERIC
Art Unit
2139
Tech Center
2100 — Computer Architecture & Software
Assignee
Pure Storage Inc.
OA Round
5 (Non-Final)
88%
Grant Probability
Favorable
5-6
OA Rounds
2y 8m
To Grant
99%
With Interview

Examiner Intelligence

Grants 88% — above average
88%
Career Allow Rate
561 granted / 640 resolved
+32.7% vs TC avg
Moderate +12% lift
Without
With
+12.0%
Interview Lift
resolved cases with interview
Typical timeline
2y 8m
Avg Prosecution
22 currently pending
Career history
662
Total Applications
across all art units

Statute-Specific Performance

§101
4.0%
-36.0% vs TC avg
§103
47.6%
+7.6% vs TC avg
§102
26.2%
-13.8% vs TC avg
§112
9.5%
-30.5% vs TC avg
Black line = Tech Center average estimate • Based on career data from 640 resolved cases

Office Action

§103
DETAILED ACTION Notice of Pre-AIA or AIA Status The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA . Continued Examination Under 37 CFR 1.114 A request for continued examination under 37 CFR 1.114, including the fee set forth in 37 CFR 1.17(e), was filed in this application after final rejection. Since this application is eligible for continued examination under 37 CFR 1.114, and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114. Applicant's submission filed on January 21st, 2026, has been entered. Response to Amendment Applicant’s Remarks/Arguments filed on January 21st, 2026, have been carefully considered. Claims 1-20 have been amended. No claims have been added or canceled. Claims 1-20 are currently pending in the instant application Claim Rejections - 35 USC § 103 In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status. The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action: A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made. The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows: 1. Determining the scope and contents of the prior art. 2. Ascertaining the differences between the prior art and the claims at issue. 3. Resolving the level of ordinary skill in the pertinent art. 4. Considering objective evidence present in the application indicating obviousness or nonobviousness. Claims 1-20 are rejected under 35 U.S.C. 103 as being unpatentable over Goel et al. [US7,958,304] in view of Ellard et al. [US8,825,938]. Goel teaches dynamically adapting the fault tolerance and performance characteristics of a RAID-based storage system by merging and splitting RAID groups. Ellard teaches use of write allocation decisions to achieve desired levels of wear across a set of redundant solid-state memory devices. Regarding claims 1, 9, and 17, Goel teaches a method comprising: detecting a change of failure characteristics for a storage device within a storage system [Goel column 3, lines 13-21 “…The dynamic reconfiguration of RAID groups is performed to adapt the RAID groups to changes in data and system characteristics. The dynamic reconfiguration includes merging and splitting RAID groups without incurring system downtime. Merging or splitting RAID groups changes fault tolerance and performance characteristics of the RAID groups, and, therefore, adapts the RAID groups to the changes in data and system characteristics…”]; and in response to the detection, changing a number of copies of metadata stored in different physical storage units within the storage device [Goel column 8, lines 4-8 “…two RAID-4 groups may be merged to form a RAID-TP group (referring to "RAID Triple Protection," which offers triple disk failure protection). In this scenario, adding a new parity disk becomes necessary, as every merged stripe needs three parity blocks…”(The examiner has determined that parity reads on the applicant’s use of the word metadata for recovery means.)], wherein the metadata is used to recover data from within the storage system [Goel column 1, lines 42-45 “…RAID-DP adds a second parity disk to each RAID group in order to provide data protection against the failure of two disks in the same RAID group…”], and Goel fails to explicitly teach wherein at least two copies of the metadata are stored within the storage device. However, Ellard does teach wherein at least two copies of the metadata are stored within the storage device [Ellard column 6, lines 16-29 “…computes the fingerprint of the data block (using, e.g., a hash function, CRC, etc.). The storage manager 21 then identifies the SSMs 7 to which the data block is to be written at 303. As noted above, in one embodiment an attempt is made to write the data block to all of the SSMs 7. In other embodiments, as described further below, an attempt is made to write the data block to more than one, but not all, of the SSMs 7, in order to accomplish wear skewing. The storage manager 21 then attempts at 304 to write the data block and its fingerprint to each of the SSMs that were identified at 303. Next, the storage manager 21 determines whether at least a quorum of the SSMs report that they have written the data block successfully 305…”]. Goel and Ellard are analogous arts in that they both deal with improving data protection with storage systems. It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to combine Goel’s detection of failure characteristics with Ellard’s storing of metadata to multiple flash memory modules for the benefit of reducing the likelihood of concurrent memory device failure and thus improve the storage lifetime [Ellard column 2, lines 55-57 “…the techniques introduced here also include a way to reduce the likelihood that substantially concurrent failures of two or more solid-state memory devices will occur…”]. Regarding claims 2, 10, and 18, as per claim 1, Goel teaches a degree of redundancy defines a number of copies of the metadata stored in the storage system [Goel column 3, lines 25-27 “…The term "fault tolerance level" herein refers to the number of parity disks used by a RAID group, as well as the data-to-parity ratio in the RAID group…”]. Regarding claims 3, 11, and 19, as per claim 1, Ellard teaches a number of copies is fewer than a number of storage devices in the storage system [Ellard column 5, lines 36-38 “…to accomplish wear skewing, the data item and fingerprint are written to some, but not all, of the SSMs 7…”]. Regarding claims 4, 12, and 20, as per claim 1, Goel teaches the failure characteristics comprise a failure rate for a plurality of storage devices [Goel column 1, lines 37 – column 2, line 2 “…high mean-time-to-failure (MTTF) and high bit error rate…a system administrator may determine the fault tolerance level based on the mean-time-to-data-loss (MTTDL) requirement in the system specification… the data-to-parity ratio needs to be rebalanced to ensure that the Mean Time to Data Loss (MTTDL) is within acceptable bounds…”]. Regarding claims 6 and 14, as per claim 1, Goel teaches the failure characteristics comprise a Redundant Array of Independent Disks (RAID) configuration for the storage system [Goel column 1, lines 40-45 “…The widespread acceptance of the SATA drives has resulted in the development and use of double-parity RAID (RAID-DP). RAID-DP adds a second parity disk to each RAID group in order to provide data protection against the failure of two disks in the same RAID group…”]. Regarding claims 7 and 15, as per claim 1, Both Goel and Ellard teach determining a degree of redundancy for the metadata comprises determining the degree of redundancy for the metadata based on a metadata type of the metadata [Goel column 12, lines 31-35 “…the first RAID I/O operation corresponds to stripes 3 and 4, which belong to the merged RAID-DP stripe group 810. I/O processing for this stripe group involves the computation of both the row (R) parity and the diagonal (D) parity, as defined by the RAID-DP protocol…”(Where the examiner has determined the row parity or the diagonal parity reads on the type of metadata)] and [Ellard column 5, lines 27-30 “…The fingerprint can be, for example, a cryptographic hash of the data represented by the item, although a simpler method, such as cyclic redundancy check (CRC), may be sufficient….”].. Regarding claims 8 and 16, as per claim 1, Goel teaches wherein changing a number of copies of the metadata stored in different physical storage units within the storage device [Goel column 10, lines 7-8 “…if a RAID group is upgraded from RAID-4 to RAID-DP by simply adding an extra parity drive to the RAID group…”] comprises storing, in different dies within the storage device, additional copies of the metadata on different dies [Ellard column 6, lines 20-29 “…the storage manager 21 then identifies the SSMs 7 to which the data block is to be written at 303. As noted above, in one embodiment an attempt is made to write the data block to all of the SSMs 7. In other embodiments, as described further below, an attempt is made to write the data block to more than one, but not all, of the SSMs 7, in order to accomplish wear skewing. The storage manager 21 then attempts at 304 to write the data block and its fingerprint to each of the SSMs that were identified at 303. Next, the storage manager 21 determines whether at least a quorum of the SSMs report that they have written the data block successfully 305…” and lines 47-52 “...It should also be noted that the system can be designed to tolerate the loss of more than one flash memory device. For example, instead of simple mirroring, a redundancy scheme such as RAID-DP, RAID-TP, or any other arbitrary coding scheme that enables arbitrary numbers of failures to be tolerated, could be used…”(The examiner has determined there is at least one embodiment where a flash memory device can be a single memory die and as such reads on the claims.)]. Claims 5 and 13 are rejected under 35 U.S.C. 103 as being unpatentable over Goel et al. [US7,958,304] in view of Ellard et al. [US8,825,938] further in view of Matosevich et al. [US2021/0373796]. Goel teaches dynamically adapting the fault tolerance and performance characteristics of a RAID-based storage system by merging and splitting RAID groups. Ellard teaches use of write allocation decisions to achieve desired levels of wear across a set of redundant solid-state memory devices. Matosevich teaches balancing resiliency and performance by selective use of degraded writes and spare capacity in storage system. Regarding claims 5 and 13, Goel and Ellard fail to explicitly teach the failure characteristics comprise an estimated rebuild time. However, Matosevich does teach the failure characteristics comprise an estimated rebuild time [Matosevich paragraph 0073, most lines “…mean time to repair (MTTR), etc…”] Goel, Ellard, and Matosevich are analogous arts in that they all deal with improving data protection with storage systems. It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to combine the teachings of Goel and Ellard with Matosevich’s repair time for the benefit of increasing the user I/O performance by throttling the rebuild process in a RAID system [Matosevich paragraph 0050, last lines “…Applying rebuild throttling will increase the time it takes to complete a rebuild operation and keep the RAID system in a degraded mode of operation, while reducing the impact on user I/O performance…”]. Response to Arguments Applicant’s arguments with respect to claims 1, 9, and 17 have been considered but are moot in view of new grounds of rejection. Conclusion Any inquiry concerning this communication or earlier communications from the examiner should be directed to ERIC CARDWELL whose telephone number is (571)270-1379. The examiner can normally be reached on Monday - Friday 10-6pm EST. Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice. If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Reginald Bragdon can be reached on (571) 272-4204. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300. Information regarding the status of an application may be obtained from the Patent Application Information Retrieval (PAIR) system. Status information for published applications may be obtained from either Private PAIR or Public PAIR. Status information for unpublished applications is available through Private PAIR only. For more information about the PAIR system, see http://pair-direct.uspto.gov. Should you have questions on access to the Private PAIR system, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative or access to the automated information system, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000. /ERIC CARDWELL/Primary Examiner, Art Unit 2139
Read full office action

Prosecution Timeline

Jun 12, 2023
Application Filed
Jun 29, 2024
Non-Final Rejection — §103
Sep 05, 2024
Applicant Interview (Telephonic)
Sep 05, 2024
Examiner Interview Summary
Oct 01, 2024
Response Filed
Jan 15, 2025
Final Rejection — §103
Feb 21, 2025
Applicant Interview (Telephonic)
Feb 21, 2025
Examiner Interview Summary
Mar 21, 2025
Request for Continued Examination
Mar 27, 2025
Response after Non-Final Action
Apr 05, 2025
Non-Final Rejection — §103
Jun 10, 2025
Response Filed
Jul 26, 2025
Final Rejection — §103
Dec 12, 2025
Applicant Interview (Telephonic)
Dec 12, 2025
Examiner Interview Summary
Jan 21, 2026
Request for Continued Examination
Jan 28, 2026
Response after Non-Final Action
Feb 05, 2026
Non-Final Rejection — §103 (current)

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Study what changed to get past this examiner. Based on 5 most recent grants.

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Prosecution Projections

5-6
Expected OA Rounds
88%
Grant Probability
99%
With Interview (+12.0%)
2y 8m
Median Time to Grant
High
PTA Risk
Based on 640 resolved cases by this examiner. Grant probability derived from career allow rate.

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