1. A device comprising: memory; one or more processors coupled to the memory; an access request process module, stored in the memory and executable by the one or more processors, that: receives a data access request from a virtual machine, determines whether data associated with the data access request is stored in a cache storage, and obtains the data associated with the data request or adds the data access request to a request array based at least in part on a determination result of whether the data associated with the data access request is stored in the cache storage; and a data transfer proxy module, stored in the memory and executable by the one or more processors, that: obtains the data access request from the request array in an event that the data associated with the data access request is not stored in the cache storage, and maps the data access request to a virtual storage unit that corresponds to a physical storage unit of a storage system.