Inducing memory device idle time through rolling read prioritizations

• US 10,270,858 B2
• Filed: 06/29/2018
• Issued: 04/23/2019
• Est. Priority Date: 09/30/2005
• Status: Active Grant

• Current Assignee: Pure Storage, Inc.
• Original Assignee: International Business Machines Corporation
• Inventors: Cocagne, Thomas D., Dhuse, Greg R.
• Primary Examiner(s): Bradley, Matthew
• Application Number:
  US16/024,669
• Publication Number:
  US 20180309829A1
• Time in Patent Office: 298 Days
• CPC Class Codes: G06F 11/1076 Parity data used in redundant arrays of independent storages, e.g. in RAID systems
• CPC Class Codes: G06F 11/1092 Rebuilding, e.g. when physically replacing a failing disk
• CPC Class Codes: G06F 2211/1028 Distributed, i.e. distributed RAID systems with parity
• CPC Class Codes: H04L 67/1097 for distributed storage of data in networks, e.g. transport arrangements for network file system [NFS], storage area networks [SAN] or network attached storage [NAS]

Abstract

A computing device includes an interface configured to interface and communicate with a dispersed storage network (DSN), a memory that stores operational instructions, and processing circuitry operably coupled to the interface and to the memory. The computing device determines to perform maintenance tasks associated with a set of memory devices of a set of storage units (SUs) of a common DSN address range. The computing device ensures that a selected number of memory devices on which the maintenance tasks are performed is less than or equal to a difference between a pillar number and a decode threshold number of dispersed error encoding parameters by which a data object is encoded and stored in the DSN. While performing the maintenance tasks, the computing device facilitates inhibiting storage of other EDSs in the set of memory devices and/or temporarily accesses at least the decode threshold number of memory devices.

Claims

1. A computing device comprising:

an interface configured to interface and communicate with a dispersed or distributed storage network (DSN);

memory that stores operational instructions; and

processing circuitry operably coupled to the interface and to the memory, wherein the processing circuitry is configured to execute the operational instructions to;

determine to perform maintenance tasks associated with a set of memory devices of a set of storage units (SUs) of a common DSN address range, wherein a data object is segmented into a plurality of data segments, wherein a data segment of the plurality of data segments is dispersed error encoded in accordance with dispersed error encoding parameters to produce a set of encoded data slices (EDSs) that is of pillar width and includes a pillar number of EDSs, wherein the set of EDSs is distributedly stored among the set of SUs, wherein a decode threshold number of EDSs are needed to recover the data segment;

select a first number of memory devices of the set of memory devices to perform the maintenance tasks, wherein the first number is less than or equal to a difference between the pillar number and the decode threshold number;

initiate performance of the maintenance tasks for the first number of memory devices of the set of memory devices;

while performing the maintenance tasks, facilitate inhibiting storage of other EDSs in the set of memory devices;

while performing the maintenance tasks, temporarily access a second number of memory devices of the set of memory devices when receiving a read data request associated with the common DSN address range, wherein the second number includes at least the decode threshold number of memory devices of the set of memory devices and excludes the first number of memory devices of the set of memory devices; and

based on detection of completion of the maintenance tasks, select a third number of memory devices of the set of memory devices to perform additional maintenance tasks, wherein the third number is also less than or equal to the difference between the pillar number and the decode threshold number, and wherein the third number of memory devices of the set of memory devices includes at least one memory device not included within the first number of memory devices of the set of memory devices.

2. The computing device of claim 1, wherein the processing circuitry is further configured to execute the operational instructions to:

select the first number of memory devices of the set of memory devices to perform the maintenance tasks based on at least one of a next set of memory devices of a list of memory devices for maintenance, a random selection, a round Robin selection, interpretation of an error message, interpretation of schedule, or interpretation of a request.

3. The computing device of claim 1, wherein the processing circuitry is further configured to execute the operational instructions to:

while performing the maintenance tasks, facilitate the inhibiting of storage of other EDSs in the set of memory devices including to;

reject a received storage request when the received storage request is associated with overwriting stored data of the common DSN address range; and

assign slice names for storage of new data associated with a new data identifier (ID) that is not included within a DSN directory such that the slice names are not associated with the common DSN address range.

4. The computing device of claim 1, wherein the processing circuitry is further configured to execute the operational instructions to:

while performing the maintenance tasks, temporarily access the second number of memory devices of the set of memory devices when receiving the read data request associated with the common DSN address range including to;

identify the second number of memory devices of the set of memory devices; and

issue read slice requests to SUs associated with the second number of memory devices of the set of memory devices receives read slice responses from at least some of the SUs associated with the second number of memory devices of the set of memory devices.

5. The computing device of claim 1, wherein:

a read threshold number of EDSs provides for reconstruction of the data segment;

a write threshold number of EDSs provides for a successful transfer of the set of EDSs from a first at least one location in the DSN to a second at least one location in the DSN;

each of the decode threshold number, the read threshold number, and the write threshold number is less than the pillar number; and

the write threshold number is greater than or equal to the read threshold number that is greater than or equal to the decode threshold number.

6. The computing device of claim 1, wherein the computing device is located at a first premises that is remotely located from a second premises of at least one SU of the set of SUs within the DSN.

7. The computing device of claim 1 further comprising:

a SU of the set of SUs within the DSN, a wireless smart phone, a laptop, a tablet, a personal computers (PC), a work station, or a video game device.

8. The computing device of claim 1, wherein the DSN includes at least one of a wireless communication system, a wire lined communication system, a non-public intranet system, a public internet system, a local area network (LAN), or a wide area network (WAN).

9. A computing device comprising:

an interface configured to interface and communicate with a dispersed or distributed storage network (DSN);

memory that stores operational instructions; and

processing circuitry operably coupled to the interface and to the memory, wherein the processing circuitry is configured to execute the operational instructions to;

determine to perform maintenance tasks associated with a set of memory devices of a set of storage units (SUs) of a common DSN address range, wherein a data object is segmented into a plurality of data segments, wherein a data segment of the plurality of data segments is dispersed error encoded in accordance with dispersed error encoding parameters to produce a set of encoded data slices (EDSs) that is of pillar width and includes a pillar number of EDSs, wherein the set of EDSs is distributedly stored among the set of SUs, wherein a decode threshold number of EDSs are needed to recover the data segment, wherein a read threshold number of EDSs provides for reconstruction of the data segment, wherein a write threshold number of EDSs provides for a successful transfer of the set of EDSs from a first at least one location in the DSN to a second at least one location in the DSN, wherein each of the decode threshold number, the read threshold number, and the write threshold number is less than the pillar number, and wherein the write threshold number is greater than or equal to the read threshold number that is greater than or equal to the decode threshold number;

select a first number of memory devices of the set of memory devices to perform the maintenance tasks based on at least one of a next set of memory devices of a list of memory devices for maintenance, a random selection, a round Robin selection, interpretation of an error message, interpretation of schedule, or interpretation of a request, wherein the first number is less than or equal to a difference between the pillar number and the decode threshold number;

initiate performance of the maintenance tasks for the first number of memory devices of the set of memory devices;

while performing the maintenance tasks, facilitate inhibiting storage of other EDSs in the set of memory devices;

while performing the maintenance tasks, temporarily access a second number of memory devices of the set of memory devices when receiving a read data request associated with the common DSN address range, wherein the second number includes at least the decode threshold number of memory devices of the set of memory devices and excludes the first number of memory devices of the set of memory devices; and

based on detection of completion of the maintenance tasks, select a third number of memory devices of the set of memory devices to perform additional maintenance tasks, wherein the third number is also less than or equal to the difference between the pillar number and the decode threshold number, and wherein the third number of memory devices of the set of memory devices includes at least one memory device not included within the first number of memory devices of the set of memory devices.

10. The computing device of claim 9, wherein the processing circuitry is further configured to execute the operational instructions to:

while performing the maintenance tasks, facilitate the inhibiting of storage of other EDSs in the set of memory devices including to;

reject a received storage request when the received storage request is associated with overwriting stored data of the common DSN address range; and

assign slice names for storage of new data associated with a new data identifier (ID) that is not included within a DSN directory such that the slice names are not associated with the common DSN address range.

11. The computing device of claim 9, wherein the processing circuitry is further configured to execute the operational instructions to:

while performing the maintenance tasks, temporarily access the second number of memory devices of the set of memory devices when receiving the read data request associated with the common DSN address range including to;

identify the second number of memory devices of the set of memory devices; and

issue read slice requests to SUs associated with the second number of memory devices of the set of memory devices receives read slice responses from at least some of the SUs associated with the second number of memory devices of the set of memory devices.

12. The computing device of claim 9 further comprising:

a SU of the set of SUs within the DSN, a wireless smart phone, a laptop, a tablet, a personal computers (PC), a work station, or a video game device.

13. The computing device of claim 9, wherein the DSN includes at least one of a wireless communication system, a wire lined communication system, a non-public intranet system, a public internet system, a local area network (LAN), or a wide area network (WAN).

14. A method for execution by a computing device, the method comprising:

determining to perform maintenance tasks associated with a set of memory devices of a set of storage units (SUs) of a common dispersed or distributed storage network (DSN) address range, wherein a data object is segmented into a plurality of data segments, wherein a data segment of the plurality of data segments is dispersed error encoded in accordance with dispersed error encoding parameters to produce a set of encoded data slices (EDSs) that is of pillar width and includes a pillar number of EDSs, wherein the set of EDSs is distributedly stored among the set of SUs, wherein a decode threshold number of EDSs are needed to recover the data segment;

selecting, via an interface of the computing device that is configured to interface and communicate with a DSN, a first number of memory devices of the set of memory devices to perform the maintenance tasks, wherein the first number is less than or equal to a difference between the pillar number and the decode threshold number;

initiating performance of the maintenance tasks for the first number of memory devices of the set of memory devices;

while performing the maintenance tasks, facilitating, via the interface, inhibiting storage of other EDSs in the set of memory devices;

while performing the maintenance tasks, temporarily accessing, via the interface, a second number of memory devices of the set of memory devices when receiving a read data request associated with the common DSN address range, wherein the second number includes at least the decode threshold number of memory devices of the set of memory devices and excludes the first number of memory devices of the set of memory devices; and

based on detection of completion of the maintenance tasks, selecting, via the interface, a third number of memory devices of the set of memory devices to perform additional maintenance tasks, wherein the third number is also less than or equal to the difference between the pillar number and the decode threshold number, and wherein the third number of memory devices of the set of memory devices includes at least one memory device not included within the first number of memory devices of the set of memory devices.

15. The method of claim 14 further comprising:

selecting the first number of memory devices of the set of memory devices to perform the maintenance tasks based on at least one of a next set of memory devices of a list of memory devices for maintenance, a random selection, a round Robin selection, interpretation of an error message, interpretation of schedule, or interpretation of a request.

16. The method of claim 14 further comprising:

while performing the maintenance tasks, facilitate the inhibiting of storage of other EDSs in the set of memory devices including to;

rejecting a received storage request when the received storage request is associated with overwriting stored data of the common DSN address range; and

assigning slice names for storage of new data associated with a new data identifier (ID) that is not included within a DSN directory such that the slice names are not associated with the common DSN address range.

17. The method of claim 14 further comprising:

while performing the maintenance tasks, temporarily accessing the second number of memory devices of the set of memory devices when receiving the read data request associated with the common DSN address range including to;

identifying the second number of memory devices of the set of memory devices; and

issuing read slice requests to SUs associated with the second number of memory devices of the set of memory devices receives read slice responses from at least some of the SUs associated with the second number of memory devices of the set of memory devices.

18. The method of claim 14, wherein:

a read threshold number of EDSs provides for reconstruction of the data segment;

a write threshold number of EDSs provides for a successful transfer of the set of EDSs from a first at least one location in the DSN to a second at least one location in the DSN;

each of the decode threshold number, the read threshold number, and the write threshold number is less than the pillar number; and

the write threshold number is greater than or equal to the read threshold number that is greater than or equal to the decode threshold number

a SU of the set of SUs within the DSN, a wireless smart phone, a laptop, a tablet, a personal computers (PC), a work station, or a video game device.

19. The method of claim 14, wherein the computing device includes a SU of the set of SUs within the DSN, a wireless smart phone, a laptop, a tablet, a personal computers (PC), a work station, or a video game device.

20. The method of claim 14, wherein the DSN includes at least one of a wireless communication system, a wire lined communication system, a non-public intranet system, a public internet system, a local area network (LAN), or a wide area network (WAN).