Server computers may include one or more input/output (I/O) adapter devices for communicating with a network and/or direct-attached device. The I/O adapter device may have limited physical resources, such as memory. Large I/O transactions may occupy all available memory on the I/O adapter device, thus causing other I/O transactions to experience intermittent and excessive delays. The I/O adapter device can be configured to issue one or more transactions for a large I/O request. Each transaction transfers a portion of the data requested by the large I/O request. When all the transactions have completed, the client that requested the large I/O request is informed that the I/O request has completed.