Soft-switch in storage system
Embodiments of the disclosure provide a method, a computer [program product and apparatus for a soft-switch in a storage system, by setting data in a source of the soft-switch to be read-only and starting a replication process of the data to a destination of the soft-switch in response to a soft-switch request; recording at the source an update operation for the data during the replication process and synchronously recording the update operation into the destination; updating the replicated data at the destination with the synchronously recorded update operation in response to the completion of the replication process; and disabling a data access to the source and enabling a data access to the destination.
1. A method for a soft-switch in a storage system, the method comprising:
setting data in a source of the soft-switch to be read-only and starting a replication process of the data to a destination of the soft-switch in response to a soft-switch request;
recording at the source an update operation for the data during the replication process and synchronously recording the update operation into the destination without updating replicated data at the destination with the update operation as long as the replication process continues;
updating replicated data at the destination with the update operation in response to completion of the replication process; and
disabling a data access to the source and enabling a data access to the destination by disconnecting a data connection with the source and establishing a data connection with the destination.
2. The method of claim 1 , wherein recording at the source an update operation for the data during the replication process and synchronously recording the update operation into the destination further comprises:
recording new data written during the replication process at the source and synchronously recording the written new data into the destination.
3. The method of claim 2 , further comprises:
creating a source cache at the source and a destination cache at the destination for recording at the source the update operation for the data and the written new data during the replication process and synchronously recording into the destination.
4. The method of claim 3 , wherein creating a source cache at the source and a destination cache at the destination for recording at the source the update operation for the data and the written new data during the replication process and synchronously recording into the destination comprises:
recording the update operation for the data and the written new data during the replication process with the source cache and synchronously recording into the destination cache.
5. The method of claim 3 , wherein the source cache and the destination cache are logically represented by data structures mirroring each other, and the data structure comprises a head including a cache pointer and an inode chain, and a body at least including the written new data.
6. The method of claim 5 , wherein the cache pointer at least stores an entrance address of the inode chain and the inode chain stores inodes recording the update operation.
7. The method of claim 2 , further comprises:
returning the data or recorded new data from the source in response to a read operation for the data or the written new data.
8. The method of claim 1 , wherein starting a replication process of the data to a destination of the soft-switch comprises:
determining the destination for the soft-switch according to a configuration of the replication process and configuring a storage space of the destination for the replication process.
9. The method of claim 1 , wherein starting a replication process of the data to a destination of the soft-switch comprises:
selecting an internal connection between the source and the destination, and
establishing a session on the selected internal connection to act as a communication pipe for the replication process.
10. The method of claim 1 , wherein updating replicated data at the destination with the update operation comprises:
using a recorded update operation as a latest snapshot of the replicated data.
11. The method of claim 1 , wherein disabling the data access to the source and enabling the data access to the destination are performed in response to updating the replicated data at the destination.
12. An apparatus for a soft-switch in a storage system, the apparatus configured for:
setting data in a source of the soft-switch to be read-only and starting a replication process of the data to a destination of the soft-switch in response to a soft-switch request;
recording at the source an update operation for the data during the replication process and synchronously recording the update operation into the destination without updating replicated data at the destination with the update operation as long as the replication process continues;
updating replicated data at the destination with the update operation in response to completion of the replication process; and
disabling a data access to the source and enabling a data access to the destination by disconnecting a data connection with the source and establishing a data connection with the destination.
13. The apparatus of claim 12 , wherein recording at the source an update operation for the data during the replication process and synchronously recording the update operation into the destination further configured for:
recording new data written during the replication process at the source and synchronously recording the written new data into the destination.
14. The apparatus of claim 13 , further configured for:
creating a source cache at the source and a destination cache at the destination for recording at the source the update operation for the data and the written new data during the replication process and synchronously recording into the destination.
15. The apparatus of claim 14 , wherein creating a source cache at the source and a destination cache at the destination for recording at the source the update operation for the data and the written new data during the replication process and synchronously recording into the destination configured for:
recording the update operation for the data and the written new data during the replication process with the source cache and synchronously recording into the destination cache.
16. The apparatus of claim 14 , wherein the source cache and the destination cache are logically represented by data structures mirroring each other, and the data structure comprises a head including a cache pointer and an inode chain, and a body at least including the written new data, wherein the cache pointer at least stores an entrance address of the inode chain and the inode chain stores inodes recording the update operation.
17. The method of claim 13 , further configured for:
returning the data or recorded new data from the source in response to a read operation for the data or the written new data.
18. The apparatus of claim 12 , wherein starting a replication process of the data to a destination of the soft-switch configured for:
determining the destination for the soft-switch according to a configuration of the replication process and configuring a storage space of the destination for the replication process.
19. The apparatus of claim 12 , wherein starting a replication process of the data to a destination of the soft-switch configured for:
selecting an internal connection between the source and the destination, and
establishing a session on the selected internal connection to act as a communication pipe for the replication process.
20. The apparatus of claim 12 , wherein updating replicated data at the destination with the update operation comprises:
using a recorded update operation as a latest snapshot of the replicated data.
21. A computer program product comprising: a non-transitory computer readable medium encoded with computer executable program code, wherein the code enables execution across one or more processors for
setting data in a source of the soft-switch to be read-only and starting a replication process of the data to a destination of the soft-switch in response to a soft-switch request;
recording at the source an update operation for the data during the replication process and synchronously recording the update operation into the destination without updating replicated data at the destination with the update operation as long as the replication process continues;
updating replicated data at the destination with the update operation in response to completion of the replication process; and
disabling a data access to the source and enabling a data access to the destination by disconnecting a data connection with the source and establishing a data connection with the destination.