TEMPORARILY STORING AN ENCODED DATA SLICE

• US 20130262959A1
• Filed: 05/06/2013
• Published: 10/03/2013
• Est. Priority Date: 04/26/2010
• Status: Active Grant

• Current Assignee: Pure Storage, Inc.
• Original Assignee: Cleversafe Incorporated (International Business Machines Corporation)
• Inventors: Resch, Jason K., Baptist, Andrew
• Granted Patent: US 9,606,858 B2
• Time in Patent Office: Days
• US Class Current: 714/766
• CPC Class Codes: G06F 11/10 Adding special bits or symbols to the coded information, e.g. parity check, casting out 9's or 11's
• CPC Class Codes: G06F 11/1076 Parity data used in redundant arrays of independent storages, e.g. in RAID systems
• CPC Class Codes: G06F 16/278 Data partitioning, e.g. horizontal or vertical partitioning
• CPC Class Codes: G06F 2211/1028 Distributed, i.e. distributed RAID systems with parity

Abstract

A processing module encodes data using a dispersed storage error coding function to produce a set of encoded data slices and identifies storage units for storage of the set of encoded data slices. The processing module determines that a storage unit of the storage units is unavailable, where the storage unit is targeted to store an encoded data slice of the set of encoded data slices. The processing module selects a foster storage unit of the storage units for temporarily storing the encoded data slice. When the storage unit is available, the processing module transfers the encoded data slice from the foster storage unit to the storage unit.

Claims

1. A method that is executed by one or more processing modules of one or more computing devices, the method comprises:

encoding data using a dispersed storage error coding function to produce a set of encoded data slices;

identifying storage units for storage of the set of encoded data slices;

determining that a storage unit of the storage units is unavailable, wherein the storage unit is targeted to store an encoded data slice of the set of encoded data slices;

selecting a foster storage unit of the storage units for temporarily storing the encoded data slice; and

when the storage unit is available, transferring the encoded data slice from the foster storage unit to the storage unit.

2. The method of claim 1, wherein the selecting the foster storage unit comprises:

determining the foster storage unit based on a desired physical proximity to the storage unit.

3. The method of claim 1, wherein the selecting the foster storage unit comprises at least one of:

determining availability of the foster storage unit;

initiating a query with the foster storage unit;

accessing a list that identifies the foster storage unit;

determining performance history of the foster storage unit; and

determining reliability history of the foster storage unit.

4. The method of claim 1 further comprises:

issuing a write request to the foster storage unit, wherein the write request includes the encoded data slice, an indication that the encoded data slice is to be stored as a foster encoded data slice, a second encoded data slice of the set of encoded data slices, and an indication that the second encoded data slice is to be permanently stored.

5. The method of claim 1, wherein the transferring the encoded data slice comprises:

detecting when the storage unit is available;

sending a transfer request to the foster storage unit and the storage unit for transferring the encoded data slice from the foster storage unit to the storage unit; and

receiving an acknowledgement of the transferring of the encoded data slice.

6. The method of claim 1, wherein the transferring the encoded data slice comprises:

when the storage unit is available, sending a notice to the storage unit that the foster storage unit is storing the encoded data slice; and

requesting, by a computing device of the one or more computing devices within the storage unit, transfer of the encoded data slice from the foster storage unit to the storage unit.

7. The method of claim 1, wherein the transferring the encoded data slice comprises:

detecting when the storage unit is available;

sending a read request to the foster storage unit regarding the encoded data slice; and

upon receiving the encoded data slice, sending the encoded data slice to the storage unit for storage therein.

8. A computing device comprises:

an interface; and

a processing module, when operable within the computing device, causes the computing device to;

encode data using a dispersed storage error coding function to produce a set of encoded data slices;

identify storage units for storage of the set of encoded data slices;

determine that a storage unit of the storage units is unavailable, wherein the storage unit is targeted to store an encoded data slice of the set of encoded data slices;

select a foster storage unit of the storage units for temporarily storing the encoded data slice; and

when the storage unit is available, transfer the encoded data slice from the foster storage unit to the storage unit.

9. The computing device of claim 8, wherein the processing module functions to select the foster storage unit by:

determining the foster storage unit based on a desired physical proximity to the storage unit.

10. The computing device of claim 8, wherein the processing module functions to select the foster storage unit by at least one of:

determining availability of the foster storage unit;

initiating, via the interface, a query with the foster storage unit;

accessing a list that identifies the foster storage unit;

determining performance history of the foster storage unit; and

determining reliability history of the foster storage unit.

11. The computing device of claim 8 further comprises:

the processing module further functions to issue, via the interface, a write request to the foster storage unit, wherein the write request includes the encoded data slice, an indication that the encoded data slice is to be stored as a foster encoded data slice, a second encoded data slice of the set of encoded data slices, and an indication that the second encoded data slice is to be permanently stored.

12. The computing device of claim 8, wherein the processing module functions to transfer the encoded data slice by:

detecting when the storage unit is available;

sending, via the interface, a transfer request to the foster storage unit and the storage unit for transferring the encoded data slice from the foster storage unit to the storage unit; and

receiving, via the interface, an acknowledgement of the transferring of the encoded data slice.

13. The computing device of claim 8, wherein the processing module functions to transfer the encoded data slice by:

when the storage unit is available, sending, via the interface, a notice to the storage unit that the foster storage unit is storing the encoded data slice; and

requesting, by another computing device within the storage unit, transfer of the encoded data slice from the foster storage unit to the storage unit.

14. The computing device of claim 8, wherein the processing module functions to transfer the encoded data slice by:

detecting when the storage unit is available;

sending, via the interface, a read request to the foster storage unit regarding the encoded data slice; and

upon receiving, via the interface, the encoded data slice, sending, via the interface, the encoded data slice to the storage unit for storage therein.