A distributed storage system including at least one storage node, and at least one object storage device (OSD) is deployed on the at least one storage node. At least one data processing device and at least one metadata processing device that has a mapping relationship with the at least one data processing device are deployed on the at least one OSD. A target data processing module of an input/output (IO) operation is configured to determine a target metadata processing device corresponding to the target data processing device and an identifier of an OSD in which the target metadata processing device is located, send an access operation to the target metadata processing device, and access data of the IO operation based on the IO operation. The target metadata processing device is configured to access metadata of the IO operation based on the access operation.