Using temporary write locations for increased power efficiency

• US 9,817,597 B2
• Filed: 11/08/2016
• Issued: 11/14/2017
• Est. Priority Date: 12/29/2009
• Status: Active Grant

• Current Assignee: Pure Storage, Inc.
• Original Assignee: International Business Machines Corporation
• Inventors: Resch, Jason K., Wozniak, Ethan S.
• Primary Examiner(s): Parry, Chris
• Assistant Examiner(s): STILTNER, WEIWEI YE
• Application Number:
  US15/345,597
• Publication Number:
  US 20170052729A1
• Time in Patent Office: 371 Days
• Field of Search: 709213
• CPC Class Codes: G06F 1/3296 by lowering the supply or operating voltage
• CPC Class Codes: G06F 11/0727 in a storage system, e.g. in a DASD or network based storage system drivers for digital recording or reproducing units G06F3/06; circuits for error detection or correction within digital recording or reproducing units G11B20/18; 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], H04L67/1097
• CPC Class Codes: G06F 11/0751 Error or fault detection not based on redundancy power supply failures G06F1/30; network fault management H04L41/06
• CPC Class Codes: G06F 11/0772 Means for error signaling, e.g. using interrupts, exception flags, dedicated error registers
• CPC Class Codes: G06F 11/079 Root cause analysis, i.e. error or fault diagnosis in a hardware test environment G06F11/22; in a software test environment G06F11/36
• CPC Class Codes: G06F 11/0793 Remedial or corrective actions recovery from an exception in an instruction pipeline G06F9/3861; by retry G06F11/1402; for recovering from a failure of a protocol instance or entity H04L69/40
• CPC Class Codes: G06F 11/1076 Parity data used in redundant arrays of independent storages, e.g. in RAID systems
• CPC Class Codes: G06F 11/22 Detection or location of defective computer hardware by testing during standby operation or during idle time, e.g. start-up testing
• CPC Class Codes: G06F 11/2221 to test input/output devices or peripheral units
• CPC Class Codes: G06F 11/28 by checking the correct order of processing G06F11/08 - G06F11/26 take precedence; monitoring patterns of pulse trains H03K5/19
• CPC Class Codes: G06F 11/3006 where the computing system is distributed, e.g. networked systems, clusters, multiprocessor systems multiprogramming arrangements G06F9/46; allocation of resources G06F9/50
• CPC Class Codes: G06F 11/3034 where the computing system component is a storage system, e.g. DASD based or network based digital input from or digital output to record carriers G06F3/06; digital recording or reproducing G11B20/18; 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], H04L67/1097
• CPC Class Codes: G06F 16/182 Distributed file systems
• CPC Class Codes: G06F 16/184 implemented as replicated file system
• CPC Class Codes: G06F 16/27 Replication, distribution or synchronisation of data between databases or within a distributed database system; Distributed database system architectures therefor
• CPC Class Codes: G06F 21/10 Protecting distributed programs or content, e.g. vending or licensing of copyrighted material protection in video systems or pay television H04N7/16 ; Digital rights management [DRM]
• CPC Class Codes: G06F 21/554 involving event detection and direct action
• CPC Class Codes: G06F 21/80 in storage media based on magnetic or optical technology, e.g. disks with sectors preventing unauthorised reproduction or copying of disc-type recordable media G11B20/00
• CPC Class Codes: G06F 2221/033 Test or assess software
• CPC Class Codes: G06F 2221/034 Test or assess a computer or a system
• CPC Class Codes: G06F 2221/2129 : Authenticate client device independently of the user
• CPC Class Codes: G06F 2221/2151 : Time stamp
• CPC Class Codes: G06F 3/0614 : Improving the reliability of storage systems
• CPC Class Codes: G06F 3/0619 : in relation to data integrity, e.g. data losses, bit errors
• CPC Class Codes: G06F 3/0625 : Power saving in storage systems
• CPC Class Codes: G06F 3/064 : Management of blocks
• CPC Class Codes: G06F 3/0647 : Migration mechanisms
• CPC Class Codes: G06F 3/065 : Replication mechanisms
• CPC Class Codes: G06F 3/0653 : Monitoring storage devices or systems
• CPC Class Codes: G06F 3/067 : Distributed or networked storage systems, e.g. storage area networks [SAN], network attached storage [NAS]
• CPC Class Codes: G06F 3/0683 : Plurality of storage devices
• CPC Class Codes: H03M 13/1515 : Reed-Solomon codes
• CPC Class Codes: H04L 1/16 : in which the return channel carries supervisory signals, e.g. repetition request signals
• CPC Class Codes: H04L 2209/34 : Encoding or coding, e.g. Huffman coding or error correction
• CPC Class Codes: H04L 41/0661 : by reconfiguring faulty entities
• CPC Class Codes: H04L 43/16 : Threshold monitoring
• CPC Class Codes: H04L 63/101 : Access control lists [ACL]
• CPC Class Codes: H04L 63/102 : Entity profiles
• CPC Class Codes: H04L 63/1416 : Event detection, e.g. attack signature detection
• CPC Class Codes: H04L 67/06 : specially adapted for file transfer, e.g. file transfer protocol [FTP]
• 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]
• CPC Class Codes: H04L 9/085 : Secret sharing or secret splitting, e.g. threshold schemes
• CPC Class Codes: H04L 9/0894 : Escrow, recovery or storing of secret information, e.g. secret key escrow or cryptographic key storage
• CPC Class Codes: H04N 21/2181 : comprising remotely distributed storage units, e.g. when movies are replicated over a plurality of video servers distributed storage of data in networks, e.g. transport arrangements for network file system [NFS], storage area networks [SAN] or network attached storage [NAS], H04L67/1097
• CPC Class Codes: H04N 21/23116 : involving data replication, e.g. over plural servers synchronization of replicated data G06F11/1658; error detection or correction by means of data replication G06F11/2053; replication in distributed file systems G06F16/10; replication in distributed file systems G06F16/27; replication or mirroring of data in data networks H04L67/1095
• CPC Class Codes: H04N 21/232 : Content retrieval operation locally within server, e.g. reading video streams from disk arrays storage management G06F3/0604; details of querying and searching of video data from a database G06F16/739
• CPC Class Codes: H04N 21/274 : Storing end-user multimedia data in response to end-user request , e.g. network recorder

Abstract

A method for a dispersed storage network (DSN) receives a data request and issues a read threshold number of read slice requests to storage units of a storage set, by receiving read slice responses from at least some of the storage units within a response timeframe and, when the received read slice responses include less than a decode threshold number of encoded data slices of a set of encoded data slices, generating at least one forced read slice request for an encoded data slice other than the received encoded data slices. The method continues by sending the at least one forced read slice requests to at least one other storage unit of the storage set and, when receiving the decode threshold number of encoded data slices, dispersed storage error decoding the received decode threshold number of encoded data slices to reproduce a data segment of the data reduce recovered data.

Claims

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 a data request;

issuing a read threshold number of read slice requests to storage units of a storage set, wherein the issuing includes;

generating the read slice requests, selecting the storage units and sending the read slice requests to the selected storage units;

receiving read slice responses from at least some of the storage units within a response timeframe;

when the received read slice responses include less than a decode threshold number of encoded data slices of a set of encoded data slices, generating at least one forced read slice request for an encoded data slice other than the received encoded data slices;

sending the at least one forced read slice requests to at least one other storage unit of the storage set, wherein the sending includes sending to a storage unit outside of the selected storage units; and

when receiving the decode threshold number of encoded data slices, dispersed storage error decoding the received decode threshold number of encoded data slices to reproduce a data segment of the recovered data.

2. The method of claim 1, wherein the selecting the storage units is based on one or more of:

a predetermination, a storage unit performance level, a storage unit availability level, or a random selection.

3. The method of claim 1, wherein the generating is based on determining a number of forced read slice requests based on a number of received encoded data slices.

4. The method of claim 3, wherein the generating further includes determining a number of forced read slice request to generate based on a difference between the decode threshold number and a number of received encoded data slices.

5. The method of claim 1, wherein the sending includes sending to a storage unit that corresponds to an error response indicating no availability unless powered up.

6. The method of claim 1, wherein the sending includes sending to temporary storage locations.

7. The method of claim 6, wherein the temporary storage locations include any of:

SSDs, RAM, or other memory devices.

8. The method of claim 7, wherein, when the temporary storage locations become full or near full, or when the memory device for which the encoded data slices are destined comes out of power-save-mode (PSM), then the storage unit flushes these temporary locations by moving the encoded data slices to the storage unit for which it was originally destined.

9. A computing device of a group of computing devices of a dispersed storage network (DSN), the computing device comprises:

an interface;

a local memory; and

a processing module operably coupled to the interface and the local memory, wherein the processing module functions to;

receive a data request;

issue a read threshold number of read slice requests to storage units of a storage set, wherein the issuing includes;

generating the read slice requests, selecting the storage units and sending the read slice requests to the selected storage units;

receive read slice responses from at least some of the storage units within a response timeframe;

when the received read slice responses include less than a decode threshold number of encoded data slices of a set of encoded data slices, generate at least one forced read slice request for an encoded data slice other than the received encoded data slices;

send the at least one forced read slice requests to at least one other storage unit of the storage set, wherein the sending includes sending to a storage unit outside of the selected storage units; and

when receiving the decode threshold number of encoded data slices, dispersed storage error decode the received decode threshold number of encoded data slices to reproduce a data segment of the recovered data.

10. The computing device of claim 9, wherein the selecting the storage units is based on one or more of:

a predetermination, a storage unit performance level, a storage unit availability level, or a random selection.

11. The computing device of claim 9, wherein the generating is based on determining a number of forced read slice requests based on a number of received encoded data slices.

12. The computing device of claim 11, wherein the generating further includes determining a number of forced read slice request to generate based on a difference between the decode threshold number and a number of received encoded data slices.

13. The computing device of claim 9, wherein the sending includes sending to a storage unit that corresponds to an error response indicating no availability unless powered up.

14. The computing device of claim 9, wherein the sending includes sending to temporary storage locations.

15. The computing device of claim 14, wherein the temporary storage locations include any of:

SSDs, RAM, or other memory devices.

16. The computing device of claim 15, wherein, when the temporary storage locations become full or near full, or when the memory device for which the encoded data slices are destined comes out of power-save-mode (PSM), then the storage unit flushes these temporary locations by moving the encoded data slices to the memory device for which it was originally destined.

17. 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 a data request;

issuing a read threshold number of read slice requests to storage units of a storage set;

receiving read slice responses from at least some of the storage units within a response timeframe;

when the received read slice responses include less than a decode threshold number of encoded data slices of a set of encoded data slices, generating at least one forced read slice request for an encoded data slice other than the received encoded data slices;

sending the at least one forced read slice requests to at least one other storage unit of the storage set, wherein the sending includes sending to a storage unit that corresponds to an error response indicating no availability unless powered up; and

when receiving the decode threshold number of encoded data slices, dispersed storage error decoding the received decode threshold number of encoded data slices to reproduce a data segment of the recovered data.