Modern data centers need to satisfy stringent low-latency for real-time interactive applications (e.g. search, web retail). However, short delay-sensitive flows often have to wait a long time for memory and link resource occupied by a few of long bandwidth-greedy flows because they share the same switch output queue (OQ). To address the above flow interference problem, this paper advocates more fine-grained flow separation in the switches than traditional OQ. We propose CQRD, a simple and cost-effective queue management scheme for data center switches, through only minor changes to the buffering and scheduling scheme. No change to the transport layer or coordination among switches is required. Simulation results show that CQRD can reduce the FCT of short flows by 20–44% in a single switch and 8–30% in a multi-stage data center switch network, only at the cost of a minor goodput decrease of large of flows.