Proxying slice access requests during a data evacuation

• US 10,073,736 B2
• Filed: 07/27/2016
• Issued: 09/11/2018
• Est. Priority Date: 07/31/2015
• Status: Active Grant

• Current Assignee: Pure Storage, Inc.
• Original Assignee: International Business Machines Corporation
• Inventors: Kazi, Asimuddin, McShane, Niall J., Motwani, Manish, Niedbala, Michael J.
• Primary Examiner(s): Rojas, Midys
• Assistant Examiner(s): Doan, Khoa D
• Application Number:
  US15/220,983
• Publication Number:
  US 20170031627A1
• Time in Patent Office: 776 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 11/108 Parity data distribution in semiconductor storages, e.g. in SSD
• CPC Class Codes: G06F 11/1662 the resynchronized component or unit being a persistent storage device re-synchronization of failed mirror storage G06F11/2082; rebuild or reconstruction of parity RAID storage G06F11/1008
• 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 13/4282 on a serial bus, e.g. I2C bus, SPI bus on daisy chain buses G06F13/4247
• CPC Class Codes: G06F 16/122 using management policies backup systems G06F11/1446; file migration policies for HSM systems G06F16/185
• CPC Class Codes: G06F 16/1824 implemented using Network-attached Storage [NAS] architecture distributed or networked storage systems G06F3/067; protocols for distributed storage of data in a network H04L67/1097
• CPC Class Codes: G06F 16/24578 using ranking
• CPC Class Codes: G06F 21/6218 to a system of files or objects, e.g. local or distributed file system or database
• CPC Class Codes: G06F 21/645 using a third party
• CPC Class Codes: G06F 2201/805 Real-time
• CPC Class Codes: G06F 3/0604 Improving or facilitating administration, e.g. storage management
• CPC Class Codes: G06F 3/0605 by facilitating the interaction with a user or administrator
• CPC Class Codes: G06F 3/061 Improving I/O performance
• CPC Class Codes: G06F 3/0619 in relation to data integrity, e.g. data losses, bit errors
• CPC Class Codes: G06F 3/0622 in relation to access
• CPC Class Codes: G06F 3/064 Management of blocks
• CPC Class Codes: G06F 3/0643 Management of files
• CPC Class Codes: G06F 3/0644 Management of space entities, e.g. partitions, extents, pools
• 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 3/0668 : adopting a particular infrastructure
• 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 3/0689 : Disk arrays, e.g. RAID, JBOD
• CPC Class Codes: H03M 13/1515 : Reed-Solomon codes
• CPC Class Codes: H03M 13/2906 : using block codes H03M13/2957 takes precedence
• CPC Class Codes: H03M 13/3761 : using code combining, i.e. using combining of codeword portions which may have been transmitted separately, e.g. Digital Fountain codes, Raptor codes or Luby Transform [LT] codes
• CPC Class Codes: H04L 63/0428 : wherein the data content is protected, e.g. by encrypting or encapsulating the payload
• CPC Class Codes: H04L 63/061 : for key exchange, e.g. in peer-to-peer networks cryptographic mechanisms or cryptographic arrangements for key agreement H04L9/0838
• CPC Class Codes: H04L 63/0853 : using an additional device, e.g. smartcard, SIM or a different communication terminal cryptographic mechanisms or cryptographic arrangements for entity authentication involving additional secure or trusted devices H04L9/3234
• CPC Class Codes: H04L 63/108 : when the policy decisions are valid for a limited amount of time
• 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 67/63 : Routing a service request depending on the request content or context
• CPC Class Codes: H04L 9/0861 : Generation of secret information including derivation or calculation of cryptographic keys or passwords

Abstract

A method begins by a processing module receiving a checked write slice request from a requesting entity. The method continues by determining that locally stored encoded data slices do not include the requested encoded data slice. The method continues by identifying an alternate location for the requested encoded data slice. The method continues by determining whether the alternate location is associated with storage of the encoded data slice. The method continues when the alternate location is associated with the storage of the encoded data slice, by issuing a favorable checked write slice response to a requesting entity. The method can include facilitating transfer of the requested encoded data slice from the alternate location to the storage unit for storage.

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:

selecting a second storage unit based on a decentralized agreement module decision decided by a decentralized agreement module, wherein the decentralized agreement module receives a ranked scoring information request from a requestor with regards to a set of candidate storage unit resources and, for each of the candidate storage unit resources, the decentralized agreement module performs a deterministic function on a location identifier (ID) of the candidate storage unit resource and an asset ID of the ranked scoring information request;

initiating an evacuation of encoded data slices from a first storage unit to the second storage unit;

receiving, at the second storage unit, a checked write slice request from a requesting entity, the checked write slice request including a requested encoded data slice;

determining that locally stored encoded data slices do not include the requested encoded data slice;

identifying an alternate location for the requested encoded data slice;

determining whether the alternate location is associated with storage of the requested encoded data slice; and

when the alternate location is associated with storage of the requested encoded data slice, issuing a favorable checked write slice response to the requesting entity.

2. The method of claim 1, wherein the checked write slice request further includes one or more of:

slice name, encoded data slice for storage, or a revision level.

3. The method of claim 2 further comprising generating a response to include one or more of:

a code associated with the checked write slice request, a name of the encoded data slice, or a revision level.

4. The method of claim 1, wherein the determining that locally stored encoded data slices do not include the requested encoded data slice includes one or more of:

performing a lookup or interpreting a query response.

5. The method of claim 1, wherein the determining whether the alternate location is associated with the requested encoded data slice includes one or more of:

issuing a checked request to the alternate location or interpreting a checked response.

6. The method of claim 1 further comprising facilitating transfer of the requested encoded data slice from the alternate location to a location of the locally stored encoded data slices for storage.

7. 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;

select a second storage unit based on a decentralized agreement module decision decided by a decentralized agreement module, wherein the decentralized agreement module receives a ranked scoring information request from a requestor with regards to a set of candidate storage unit resources and, for each of the candidate storage unit resources, the decentralized agreement module performs a deterministic function on a location identifier (ID) of the candidate storage unit resource and an asset ID of the ranked scoring information request;

initiate an evacuation of encoded data slices from a first storage unit to the second storage unit;

receive, at the second storage unit, a checked write slice request from a requesting entity, the checked write slice request including a requested encoded data slice;

determine whether the alternate location is associated with storage of the requested encoded data slice; and

when the alternate location is associated with storage of the requested encoded data slice, issue a favorable checked write slice response to the requesting entity.

8. The computing device of claim 7, wherein the checked write slice request further includes one or more of:

slice name, encoded data slice for storage, or a revision level.

9. The computing device of claim 7 further comprising generating a response to include one or more of:

a code associated with the checked write slice request, a name of the encoded data slice, or a revision level.

10. The computing device of claim 7, wherein the determining that locally stored encoded data slices do not include the requested encoded data slice includes one or more of:

performing a lookup or interpreting a query response.

11. The computing device of claim 7, wherein the determining whether the alternate location is associated with the requested encoded data slice includes one or more of:

issuing a checked request to the alternate location or interpreting a checked response.

12. The computing device of claim 7 further comprising facilitating transfer of the requested encoded data slice from the alternate location to a location of the locally stored encoded data slices for storage.

13. 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:

selecting a second storage unit based on a decentralized agreement module decision decided by a decentralized agreement module, wherein the decentralized agreement module receives a ranked scoring information request from a requestor with regards to a set of candidate storage unit resources and, for each of the candidate storage unit resources, the decentralized agreement module performs a deterministic function on a location identifier (ID) of the candidate storage unit resource and an asset ID of the ranked scoring information request;

receiving, during an evacuation of encoded data slices from a first storage unit to the second storage unit, a checked write slice request at the second storage unit from a requesting entity, the checked write slice request including a requested encoded data slice;

determining that locally stored encoded data slices do not include the requested encoded data slice;

identifying an alternate location for the requested encoded data slice;

determining whether the alternate location is associated with storage of the requested encoded data slice; and

when the alternate location is associated with storage of the requested encoded data slice, issuing a favorable checked write slice response to the requesting entity.

14. The method of claim 13, wherein the checked write slice request further includes one or more of:

slice name, encoded data slice for storage, or a revision level.

15. The method of claim 13 further comprising generating a response to include one or more of:

a code associated with the checked write slice request, a name of the encoded data slice, or a revision level.

16. The method of claim 13, wherein the determining that locally stored encoded data slices do not include the requested encoded data slice includes one or more of:

performing a lookup or interpreting a query response.

17. The method of claim 13, wherein the determining whether the alternate location is associated with the requested encoded data slice includes one or more of:

issuing a checked request to the alternate location or interpreting a checked response.

18. The method of claim 13 further comprising facilitating transfer of the requested encoded data slice from the alternate location to a location of the locally stored encoded data slices for storage.