Abstract: Data migration is facilitated. An example method comprises initiating data migration from a first storage system to a second storage system, wherein the data migration is divided into stages, and the stages comprise a first stage and a second stage after the first stage. The method comprises executing tasks in a first group of tasks in the first stage in parallel, wherein the tasks comprise a first task and a second task. The method further comprises generating a third task corresponding to the first task and a fourth task corresponding to the second task in the second stage in response to determining that the first task and the second task are completed respectively. For instance, in the staged data migration process, multiple execution tasks in different stages can be executed in parallel, and thus the speed of data migration is increased and fault tolerance performance of the system is improved.

Abstract: The present disclosure relates to managing an index of a storage system. For instance, update requests are divided into groups of update requests, the update requests being used to update data items in the storage system respectively. Regarding a target update request in a group of update requests among the groups of update requests, a target leaf node in the index is determined, the target leaf node comprising a target data item that is to be updated according to the target update request. The target leaf node is updated based on the target update request. In response to determining all to-be-updated data items in the target leaf node have been updated, the updated target leaf node is added to a write queue of the storage system. Accordingly, the index of the storage system is accessible with higher efficiency, and further the overall performance of the storage system may be improved.

Abstract: Data migration is facilitated. An example method comprises initiating data migration from a first storage system to a second storage system, wherein the data migration is divided into stages, and the stages comprise a first stage and a second stage after the first stage. The method comprises executing tasks in a first group of tasks in the first stage in parallel, wherein the tasks comprise a first task and a second task. The method further comprises generating a third task corresponding to the first task and a fourth task corresponding to the second task in the second stage in response to determining that the first task and the second task are completed respectively. For instance, in the staged data migration process, multiple execution tasks in different stages can be executed in parallel, and thus the speed of data migration is increased and fault tolerance performance of the system is improved.