An active layer of the index includes a first shard group, and shards in the first shard group are configured to store indexes of a part of data objects in a streaming storage system. In response to determining that the state of the first shard group meets a predetermined expansion condition, a second shard group is created in the index, and shards in the second shard group are configured to store indexes of data objects that will enter the storage system. The storage system is managed based on the shards in an active layer (where the second shard group is located) and frozen layers (where the second shard group) in the index. The number of shards in the storage system can be dynamically set to process streaming data at a relatively high speed, and it is suitable for processing streaming data that continuously enters the storage system.