“Prioritized Data Reconstruction In A Dispersed Storage Network” in Patent Application Approval Process (USPTO 20190258546)

2019 SEP 11 (NewsRx) -- By a News Reporter-Staff News Editor at Information Technology Business Daily -- A patent application by the inventors Volvovski, Ilya (Chicago, IL); Baptist, Andrew D. (Mt. Pleasant, WI); Resch, Jason K. (Chicago, IL); Leggette, Wesley B. (Chicago, IL), filed on May 2, 2019, was made available online on August 22, 2019, according to news reporting originating from Washington, D.C., by NewsRx correspondents.

This patent application is assigned to International Business Machines Corporation (Armonk, New York, United States).

The following quote was obtained by the news editors from the background information supplied by the inventors: “This invention relates generally to computer networks and, more specifically, to rebuilding data in a dispersed storage network.

“Computing devices are known to communicate data, process data, and/or store data. Such computing devices range from wireless smart phones, laptops, tablets, personal computers (PC), work stations, and video game devices, to data centers that support millions of web searches, stock trades, or on-line purchases every day. In general, a computing device includes a central processing unit (CPU), a memory system, user input/output interfaces, peripheral device interfaces, and an interconnecting bus structure.

“As is further known, a computer may effectively extend its CPU by using ‘cloud computing’ to perform one or more computing functions (e.g., a service, an application, an algorithm, an arithmetic logic function, etc.) on behalf of the computer. Further, for large services, applications, and/or functions, cloud computing may be performed by multiple cloud computing resources in a distributed manner to improve the response time for completion of the service, application, and/or function. For example, Hadoop is an open source software framework that supports distributed applications enabling application execution by thousands of computers.

“In addition to cloud computing, a computer may use ‘cloud storage’ as part of its memory system. As is known, cloud storage enables a user, via its computer, to store files, applications, etc. on a remote storage system. The remote storage system may include a RAID (redundant array of independent disks) system and/or a dispersed storage system that uses an error correction scheme to encode data for storage.

“In a RAID system, a RAID controller adds parity data to the original data before storing it across an array of disks. The parity data is calculated from the original data such that the failure of a single disk typically will not result in the loss of the original data. While RAID systems can address certain memory device failures, these systems may suffer from effectiveness, efficiency and security issues. For instance, as more disks are added to the array, the probability of a disk failure rises, which may increase maintenance costs. When a disk fails, for example, it needs to be manually replaced before another disk(s) fails and the data stored in the RAID system is lost. To reduce the risk of data loss, data on a RAID device is often copied to one or more other RAID devices. While this may reduce the possibility of data loss, it also raises security issues since multiple copies of data may be available, thereby increasing the chances of unauthorized access. In addition, co-location of some RAID devices may result in a risk of a complete data loss in the event of a natural disaster, fire, power surge/outage, etc.”

In addition to the background information obtained for this patent application, NewsRx journalists also obtained the inventors’ summary information for this patent application: “According to embodiments of the present disclosure, novel methods and systems are presented for use in a dispersed storage network (DSN) to prioritize data rebuilding operations. In various examples, a computing device (e.g., an integrity processing unit) of the DSN receives data loss information from a set of storage units of the DSN. Based on the data loss information, the computing device detects one or more slice errors regarding data stored by the set of storage units. In response to detecting slice errors, the computing device issues rebuild requests to the set of storage units for data associated with the slice errors. The computing device also determines a rebuild rate based on a rate of rebuilding associated with the rebuild requests. The computing device further receives storage error information regarding errors associated with storage requests to the set of storage units and, based on the data loss information and storage error information, determines a data loss rate. The rebuild rate and the data loss rate are provided to the set of storage units for use in determining whether to prioritize the rebuild requests. For example, when the rebuild rate compares unfavorably to the data loss rate, rebuild requests are prioritized over the storage requests, thereby minimizing any potential for irreversible data loss.”

The claims supplied by the inventors are:

“1. A method for execution by one or more processing modules of one or more computing devices of a dispersed storage network (DSN), the method comprises: receiving data loss information from a set of storage units of the DSN; based on the data loss information, detecting one or more slice errors associated with data stored by the set of storage units; in response to detecting the one or more slice errors, issuing rebuild requests to one or more storage units of the set of storage units for data associated with the one or more slice errors; receiving storage error information regarding errors associated with storage requests, to the set of storage units, for one or more encoded data slices; generating a rebuild rate based on a rate of rebuilding associated with the rebuild requests; generating a data loss rate based on the data loss information and the storage error information; and outputting the rebuild rate and the data loss rate to the set of storage units for use in determining whether to prioritize the rebuild requests.

“2. The method of claim 1, further comprising: receiving, by a storage unit of the set of storage units, the rebuild rate and the data loss rate; determining, by the storage unit, whether the rebuild rate compares unfavorably to the data loss rate; and in response to determining that the rebuild rate compares unfavorably to the data loss rate, prioritizing, by the storage unit, the rebuild requests over the storage requests.

“3. The method of claim 2, further comprising: in response to determining that the rebuild rate compares favorably to the data loss rate, prioritizing, by the storage unit, the storage requests over the rebuild requests.

“4. The method of claim 2, wherein the rebuild rate compares unfavorably to the data loss rate when the rebuild rate is less than the data loss rate.

“5. The method of claim 2, wherein the rebuild rate compares unfavorably to the data loss rate when the rebuild rate is greater than the data loss rate and a difference between the rebuild rate and the data loss rate is less than a predetermined threshold.

“6. The method of claim 2, wherein the rebuild rate compares unfavorably to the data loss rate when the rebuild rate is greater than the data loss rate and a difference between the rebuild rate and the data loss rate is less than a predetermined threshold.

“7. The method of claim 3, wherein the rebuild rate compares favorably to the data loss rate when the rebuild rate is greater than the data loss rate by more than a predetermined threshold.

“8. The method of claim 1, wherein the data loss information includes a rate of data loss due to slice errors, the slice errors relating to at least one of missing encoded data slices, corrupted encoded data slices, or a memory failure.

“9. The method of claim 1, wherein the storage error information includes a portion of the data loss rate due to data written to the set of storage units, via the storage requests, but not stored by the set of storage units, and wherein the storage requests include, respectively, a write slice request that includes a slice name and an encoded data slice.

“10. The method of claim 1, wherein the rebuild requests include at least one of a request to rebuild an encoded data slice, a request for a partially encoded slice, a request to scan an encoded data slice for error, or a request to retrieve a slice for a rebuild operation.

“11. A computing device of a dispersed storage network (DSN), the computing device comprises: a network interface; a memory comprising instructions; and one or more processing modules in communication with the memory, wherein the one or more processing modules execute the instructions to: receive, via the network interface, data loss information from a set of storage units of the DSN; based on the data loss information, detect one or more slice errors associated with data stored by the set of storage units; in response to detecting the one or more slice errors, issue rebuild requests to one or more storage units of the set of storage units for data associated with the one or more slice errors; receive storage error information regarding errors associated with storage requests, to the set of storage units, for one or more encoded data slices; generate a rebuild rate based on a rate of rebuilding associated with the rebuild requests; generate a data loss rate based on the data loss information and the storage error information; and output, via the network interface, the rebuild rate and the data loss rate to the set of storage units for use in determining whether to prioritize the rebuild requests.

“12. The computing device of claim 11, wherein the data loss information includes a rate of data loss due to slice errors.

“13. The computing device of claim 12, wherein the slice errors relate to at least one of missing encoded data slices, corrupted encoded data slices, or a memory failure.

“14. The computing device of claim 11, wherein the storage error information includes a portion of the data loss rate due to data written to the set of storage units, via the storage requests, but not stored by the set of storage units.

“15. The computing device of claim 11, wherein the rebuild requests include at least one of a request to rebuild an encoded data slice, a request for a partially encoded slice, a request to scan an encoded data slice for error, or a request to retrieve a slice for a rebuild operation.

“16. A distributed storage network (DSN) comprising: a plurality of storage units logically organized into DSN memories, each of the plurality of storage units including memory devices configured to store error encoded data slices; a computing device coupled to the plurality of storage units; each storage unit including a one or more processing modules in communication with a local memory comprising instructions, wherein the one or more processing modules execute the instructions to: send, to the computing device, data loss information; receive, from the computing device, a rebuild rate and a data loss rate, wherein the rebuild rate is based on a rate of rebuilding data associated with rebuild requests received by the plurality of storage units, and wherein the data loss rate is based on the data loss information and storage error information regarding errors associated with storage requests to the plurality of storage units; determine whether the rebuild rate compares unfavorably to the data loss rate; and in response to determining that the rebuild rate compares unfavorably to the data loss rate, prioritizing the rebuild requests over the storage requests.

“17. The DSN of claim 16, wherein the one or more processing modules further execute the instructions to: in response to determining that the rebuild rate compares favorably to the data loss rate, prioritizing the storage requests over the rebuild requests.

“18. The DSN of claim 17, wherein the rebuild rate compares favorably to the data loss rate when the rebuild rate is greater than the data loss rate by more than a predetermined threshold.

“19. The DSN of claim 16, wherein the rebuild rate compares unfavorably to the data loss rate when the rebuild rate is less than the data loss rate.

“20. The DSN of claim 16, wherein the rebuild rate compares unfavorably to the data loss rate when the rebuild rate is greater than the data loss rate and a difference between the rebuild rate and the data loss rate is less than a predetermined threshold.”

URL and more information on this patent application, see: Volvovski, Ilya; Baptist, Andrew D.; Resch, Jason K.; Leggette, Wesley B. Prioritized Data Reconstruction In A Dispersed Storage Network. Filed May 2, 2019 and posted August 22, 2019. Patent URL: http://appft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220190258546%22.PGNR.&OS=DN/20190258546&RS=DN/20190258546

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