Data backup method, apparatus, and system

A data backup method performed in a storage system having a first storage device comprising a first logical unit number (LUN), a second storage device comprising a second LUN in an active-active relationship with the first LUN of the first storage device, and a backup storage device, the method comprising:

• setting, by the first storage device, a dual-ended backup policy, wherein the dual-ended backup policy comprises a first backup policy to be performed by the first storage device for the first LUN and a second backup policy to be performed by the second storage device for the second LUN, wherein the first storage device initiates backup for the first LUN according to the first backup policy;
• hanging, by the first storage device, an input/output (IO) request from a host, and writing, into a hard disk, write request previously cached in the first storage device, wherein hanging the IO request from the host means that the IO received from the host is placed in a cache and is not processed temporarily;
• sending, by the first storage device, a notification message to the second storage device in response to hanging the IO from the host, wherein the notification message is used to instruct the second storage device to hang IO from the host and create a snapshot for the second LUN;
• and
• receiving, by the first storage device, a snapshot identifier for the second LUN returned by the second storage device, creating a snapshot for the first LUN, creating a backup image of the current backup in the backup storage device, and writing differential data between the created snapshot for the first LUN and a previous snapshot into the backup image.

A storage device comprising:

• a memory storing executable instructions;
• a processor configured to executable the executable instructions to perform operations of:
• setting a dual-ended backup policy, wherein the dual-ended backup policy comprises a first backup policy to be performed by the storage device for a first logical unit number (LUN) of the storage device and a second backup policy to be performed by a second storage device for a second LUN of the second storage device, wherein the first storage device initiates backup for the first LUN according to the first backup policy;
• sending, to the second storage device, a request message, wherein the request message comprises an IO data status record of a first LUN of the storage device, and the IO data status record records IO saved to storage in the first LUN, wherein the second LUN is in an active-to-active relationship with the first LUN;
• receiving, from the second storage device, a response message comprising information regarding the data consistency points, wherein the data consistency points indicate IO that has been saved to both the storage in the first LUN and the storage in the second LUN;
• creating a snapshot for the first LUN based on the data consistency points;
• and
• providing differential data between the created snapshot and a previous snapshot, wherein the differential data is written into a backup image for the created snapshot in the backup storage device.

A storage system comprising:

• a first storage device having a first logical unit number (LUN);
• a second storage device having a second LUN, wherein the first LUN and the second LUN are in an active-active relationship;
• and
• a backup storage device;
• wherein the first storage device is coupled to the second storage device and the backup storage device, respectively;
• wherein the first storage device is configured to perform operations of:
• setting a dual-ended backup policy, wherein the dual-ended backup policy comprises a first backup policy to be performed by the first storage device for the first LUN and a second backup policy to be performed by the second storage device for the second LUN, wherein the first storage device initiates backup for the first LUN according to the first backup policy;
• sending, to the second storage device, a request message, wherein the request message comprises an IO data status record of a first LUN of the storage, and the IO data status record records IO saved to storage in the first LUN;
• receiving, from the second storage device, a response message comprising information regarding the data consistency points, wherein the data consistency points indicate IO that has been saved to both the storage in the first LUN and the storage in the second LUN;
• creating a snapshot for the first LUN based on the data consistency points;
• providing differential data between the created snapshot and a previous snapshot, wherein the differential data is written into a backup image for the created snapshot in the backup storage device;
• wherein the second storage device is configured to perform operations of:
• receiving the request message from the first storage device;
• obtaining, in response to the request message, information regarding the data consistency points based on the IO data status record of the first LUN and an IO data status record of the second LUN stored in the second storage device, wherein the IO data status record of the second LUN records IO writing logs regarding IO saved to storage in the second LUN;
• and
• sending the information regarding the data consistency points to the first storage device.