METHOD OF EFFICIENTLY MIGRATING DATA FROM ONE TIER TO ANOTHER WITH SUSPEND AND RESUME CAPABILITY

• US 20200133719A1
• Filed: 10/24/2018
• Published: 04/30/2020
• Est. Priority Date: 10/24/2018
• Status: Active Grant

• Current Assignee: Emc IP Holding Company LLC (Dell Technologies Inc.)
• Original Assignee: Emc IP Holding Company LLC (Dell Technologies Inc.)
• Inventors: Chinthekindi, Ramprasad, Duggal, Abhinav, Srinivasan, Srikanth, Bai, Lan
• Granted Patent: US 10,929,176 B2
• Time in Patent Office: Days
• 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 11/0763 by bit configuration check, e.g. of formats or tags
• CPC Class Codes: G06F 11/1438 Restarting or rejuvenating
• CPC Class Codes: G06F 11/1441 Resetting or repowering
• CPC Class Codes: G06F 16/119 Details of migration of file systems migration mechanisms in storage systems G06F3/0647
• CPC Class Codes: G06F 16/185 Hierarchical storage management [HSM] systems, e.g. file migration or policies thereof details of archiving G06F16/11
• CPC Class Codes: G06F 2201/83 the solution involving signatures
• CPC Class Codes: G06F 3/0604 Improving or facilitating administration, e.g. storage management
• CPC Class Codes: G06F 3/0608 Saving storage space on storage systems
• CPC Class Codes: G06F 3/0641 De-duplication techniques
• 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 3/0649 Lifecycle management
• 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 3/0685 Hybrid storage combining heterogeneous device types, e.g. hierarchical storage, hybrid arrays
• CPC Class Codes: G06F 9/4868 with creation or replication
• CPC Class Codes: H04L 9/0643 Hash functions, e.g. MD5, SHA, HMAC or f9 MAC

Abstract

In an embodiment, a system and method for supporting a seeding process with suspend and resume capabilities are described. A resumable seeding component in a data seeding module can be used to move data from a source tier to a target tier. A resumption context including a perfect hash function (PHF) and a perfect hash vector (PHV) persists a state of a seeding process at the end of each operation in the seeding process. The PHV represents data segments of the data using the PHF. The resumption context is loaded into memory upon resumption of the seeding process after it is suspended. Information in the resumable context is used to determine a last successfully completed operation, and a last copied container. The seeding process is resumed by executing an operation following the completed operation in the resumable context.

Claims

1. A computer-implemented method for cross-tier data migration in a storage system, the method comprising:

receiving, at a seeding module executing in the storage system, a request for migrating a plurality of files from a source tier to a target tier in the storage system, wherein the files correspond to a plurality of containers, each container with a container identifier;

in response to the request, migrating, by the seeding module, data segments in the plurality of containers by performing a plurality of sequential operations, wherein the seeding module includes a resumption context for maintaining a state of the plurality of sequential operations, the state indicating a last successful operation of the plurality of sequential operations;

detecting, by the seeding module, that the data migration is suspended;

checking the resumption context to determine the last successful operation;

resuming the migration of the containers by performing an operation following the last successful operation.

2. The method of claim 1, wherein the plurality of sequential operations includes a copying operation, which copies a subset of the plurality of containers from the source tier to the target tier.

3. The method of claim 2, wherein the seeding module stores a container identifier of a last copied container of the subset of the plurality of containers in the resumption context, such that in the event of a failure of the copying operation, the seeding module is to resume copying from the last copied container.

4. The method of claim 1, wherein the suspending of the data migration is caused by one or more of an execution of a garbage collector, a network disconnection, a system crash, or a user intervention.

5. The method of claim 1, wherein the first source tier is an active tier, and the target tier is a cloud tier.

6. The method of claim 1, wherein the resumption context further includes perfect hash functions (PHFs), perfect hash vectors (PHVs), wherein the PHFs and PHVs create a collision-free mapping between the plurality of files and the plurality of containers.

7. The method of claim 1, wherein the plurality of operations further includes an install operation, which is to update locations of the files to point to the target tier.

8. The non-transitory machine-readable medium having instructions stored therein, which when executed by a processor, cause the processor to perform operations comprising:

receiving, at a seeding module executing in the storage system, a request for migrating a plurality of files from a source tier to a target tier in the storage system, wherein the files correspond to a plurality of containers, each container with a container identifier;

in response to the request, migrating, by the seeding module, data segments in the plurality of containers by performing a plurality of sequential operations, wherein the seeding module includes a resumption context for maintaining a state of the plurality of sequential operations, the state indicating a last successful operation of the plurality of sequential operations;

detecting, by the seeding module, that the data migration is suspended;

checking the resumption context to determine the last successful operation;

resuming the migration of the containers by performing an operation following the last successful operation.

9. The non-transitory machine-readable medium of claim 8, wherein the plurality of sequential operations includes a copying operation, which copies a subset of the plurality of containers from the source tier to the target tier.

10. The non-transitory machine-readable medium of claim 9, wherein the seeding module stores a container identifier of a last copied container of the subset of the plurality of containers in the resumption context, such that in the event of a failure of the copying operation, the seeding module is to resume copying from the last copied container.

11. The non-transitory machine-readable medium of claim 8, wherein the suspending of the data migration is caused by one or more of an execution of a garbage collector, a network disconnection, a system crash, or a user intervention.

12. The non-transitory machine-readable medium of claim 8, wherein the first source tier is an active tier, and the target tier is a cloud tier.

13. The non-transitory machine-readable medium of claim 8, wherein the resumption context further includes perfect hash functions (PHFs), perfect hash vectors (PHVs), wherein the PHFs and PHVs create a collision-free mapping between the plurality of files and the plurality of containers.

14. The non-transitory machine-readable medium of claim 8, wherein the plurality of operations further includes an install operation, which is to update locations of the files to point to the target tier.

15. A data processing system, comprising:

a processor;

a memory coupled to the processor to store instructions, which when executed by the processor, cause the processor to perform operations, the operations

receiving, at a seeding module executing in the storage system, a request for migrating a plurality of files from a source tier to a target tier in the storage system, wherein the files correspond to a plurality of containers, each container with a container identifier;

in response to the request, migrating, by the seeding module, data segments in the plurality of containers by performing a plurality of sequential operations, wherein the seeding module includes a resumption context for maintaining a state of the plurality of sequential operations, the state indicating a last successful operation of the plurality of sequential operations;

detecting, by the seeding module, that the data migration is suspended;

checking the resumption context to determine the last successful operation;

resuming the migration of the containers by performing an operation following the last successful operation.

16. The system of claim 15, wherein the plurality of sequential operations includes a copying operation, which copies a subset of the plurality of containers from the source tier to the target tier.

17. The system of claim 16, wherein the seeding module stores a container identifier of a last copied container of the subset of the plurality of containers in the resumption context, such that in the event of a failure of the copying operation, the s4eeding module is to resume copying from the last copied container.

18. The system of claim of claim 15, wherein the suspending of the data is caused by one or more of an execution of a garbage collector, a network disconnection, a system crash, or a user intervention.

19. The system of claim of claim 15, wherein the first source tier is an active tier, and the target tier is a cloud tier.

20. The system of claim of claim 15, wherein the resumption context further includes perfect hash functions (PHFs), perfect hash vectors (PHVs), wherein the PHFs and PHVs create a collision-free mapping between the plurality of files and the plurality of containers.