Method for using write intents in a distributed storage network

• US 9,998,147 B1
• Filed: 02/27/2017
• Issued: 06/12/2018
• Est. Priority Date: 02/27/2017
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Dubucq, Thomas, Jarczyk, Jeremy S., Khadiwala, Ravi V., Motwani, Manish, Narubin, Renars W., Resch, Jason K., Scholl, Daniel J., Vedpathak, Yogesh R.
• Primary Examiner(s): Chaudry, Mujtaba M
• Application Number:
  US15/442,744
• Time in Patent Office: 470 Days
• Field of Search: None
• CPC Class Codes: G06F 11/1076 Parity data used in redundant arrays of independent storages, e.g. in RAID systems
• CPC Class Codes: H03M 13/05 using block codes, i.e. a predetermined number of check bits joined to a predetermined number of information bits H03M13/2906 takes precedence
• CPC Class Codes: H03M 13/1515 Reed-Solomon codes
• 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: H03M 13/6566 Implementations concerning memory access contentions
• 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 method beings by a computing device receiving a write request for a data segment that has been encoded to produce a set of encoded data slices. The method continues with the write request being stored in memory and a write intent associated with the write request being created and stored as an object in memory. The computing device then determines whether metadata associated with the data segment can be updated, and when the metadata cannot be updated maintaining the write request in memory until a cleanup agent can execute the write intent and successfully update the metadata.

Claims

1. A method comprises:

receiving, by a computing device, a write request intended for one or more storage units of a dispersed storage network (DSN), wherein the write request is for data segment that has been encoded to produce a set of encoded data slices;

storing the write request in memory;

creating a write intent associated with the write request, wherein the write intent includes information about storage of the set of encoded data slices;

determining whether metadata associated with the write request can be successfully updated;

when the metadata associated with the write request can be successfully updated, deleting the write intent associated with the write request;

when the metadata associated with the write request cannot be successfully updated, maintaining the write request in memory until a cleanup agent can execute the write request; and

executing the write request using the write intent associated with the write request.

2. The method of claim 1 further comprises:

listing, by the cleanup agent, the unfinished write intent before executing the write request.

3. The method of claim 1, wherein the metadata includes a quota limit for the number of objects permitted for storage in a container.

4. The method of claim 1, wherein the metadata includes a quota limit for the amount of data permitted for storage in a container.

5. The method of claim 1, wherein the write request is an atomic transactional operation.

6. The method of claim 5, wherein the atomic transactional operation is a multi-element compare and swap.

7. The method of claim 1, wherein the write intent includes at least one of:

changes in data segment size or changes in number of object.

8. The method of claim 1, wherein the metadata includes information associated with a particular DSN user.

9. The method of claim 1, wherein the write intent includes quota limit information for a particular DSN user.

10. A computing device comprises:

an interface for interfacing with a network;

memory; and

a processing module operably coupled to the interface and to the memory, wherein the processing module is operable to;

receive, by a computing device, a write request intended for one or more storage units of a dispersed storage network (DSN), wherein the write request is for data segment that has been encoded to produce a set of encoded data slices;

store the write request in memory;

create a write intent associated with the write request, wherein the write intent includes information about storage of the set of encoded data slices;

determine whether metadata associated with the write request can be successfully updated;

when the metadata associated with the write request can be successfully updated, deleting the write intent associated with the write request;

when the metadata associated with the write request cannot be successfully updated, maintain the write request in memory until a cleanup agent can execute the write request; and

execute the write request using the write intent associated with the write request.

11. The computing device of claim 10 wherein the processing module is further operable to:

list, by the cleanup agent, the unfinished write intent before executing the write request.

12. The computing device of claim 10, wherein the metadata includes a quota limit for the number of objects permitted for storage in a container.

13. The computing device of claim 10, wherein the metadata includes a quota limit for the amount of data permitted for storage in a container.

14. The computing device of claim 10, wherein the write request is an atomic transactional operation.

15. The computing device of claim 14, wherein the atomic transactional operation is a multi-element compare and swap operation.

16. The computing device of claim 10, wherein the write intent includes at least one of:

changes in data segment size or changes in number of object.

17. The computing device of claim 10, wherein the metadata includes information associated with a user.

18. The computing device of claim 10, wherein the write intent includes quota limit information for a particular DSN user.

19. A method performed in a distributed storage (DS) unit of a distributed storage network (DSN), the method comprises:

receiving a write request from the dispersed storage network (DSN), wherein the write request is for data segment that has been encoded to produce a set of encoded data slices;

storing the write request in memory;

creating a write intent associated with the write request, wherein the write intent includes information about storage of the set of encoded data slices;

determining whether metadata associated with the write request can be successfully updated;

when the metadata associated with the write request can be successfully updated, deleting the write intent associated with the write request;

when the metadata associated with the write request cannot be successfully updated, maintaining the write request in memory until a cleanup agent can execute the write request; and

executing the write request using the write intent associated with the write request.

20. The method of claim 19, wherein the write request is an atomic transactional operation.