Technical solutions are described for executing a plurality of computer-executable synchronous input/output (I/O) commands received by a storage control unit in a multiple virtual storage system. An example method includes receiving a set of synchronous I/O commands, each of the commands received from a respective operating system from a plurality of operating systems. The method further includes selecting, from the set of synchronous I/O operations, a subset of synchronous I/O commands, and allocating a shared resource to the subset of synchronous I/O commands. The method further includes executing each synchronous I/O command from the selected subset of synchronous I/O commands concurrently.