Asynchronous input and output for snapshots of virtual machines

A data management system comprises: a storage appliance configured to store a snapshot of a virtual machine; and one or more processors in communication with the storage appliance. The one or more processors are configured to perform operations including: identifying a plurality of shards of the virtual machine; requesting a snapshot of each of the plurality of shards; receiving the shards asynchronously; ordering the received snapshot shards sequentially into a results queue; and storing a single snapshot of the virtual machine based on the ordered snapshot shards. Operations may further include maintaining a flow control queue that limits the number of snapshot shards requested.