Virtual storage arrays consolidate data storage at a data center for physical and virtual computer systems at one or more branch network locations. Standalone and virtualized computer systems at a branch network location load, execute, and store their operating systems, applications, and data using virtual storage arrays and do not require any built-in or external non-volatile data storage devices such as hard disk drives or solid-state drives at the branch network location. The virtual disks of the virtual storage array are mapped to physical data storage at the data center and accessed via a WAN using storage block-based protocols. A storage block cache at the branch network location includes storage blocks prefetched based on knowledge about the computer systems at the branch network location and the behavior of their operating systems and applications.