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: Metadata of a storage object is managed. For instance, in response to metadata of a storage object being updated, a first index structure for indexing the metadata of the storage object and a page table corresponding to the first index structure in a memory are updated, wherein the first index structure and the page table have been stored in a persistent storage device. Updates of the page table are recorded in at least one page table journal and the updated first index structure and the at least one page table journal are stored in the persistent storage device. Embodiments can significantly increase the speed of failover and persistence of metadata in a distributed object storage system.

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.