Embodiments are described for prioritizing input/output (I/O) operations dispatched from a storage media to a host bus adapter in a network, by tagging, in an I/O tagging module, the I/O operations in a file system supporting applications generating the I/O operations, wherein all child I/O operations initiated from a parent I/O operation are tagged with a same unique tag ID; tracking a time of arrival of each I/O operation of the I/O operations; and dispatching, in a transactional I/O scheduler, all sibling I/O's of the parent I/O operation based on a unique tag ID for the sibling I/Os, a respective time of arrival of each of the sibling I/Os, and defined quality of service (QoS) requirements.