Geo-distributed consensus protocols underpin modern databases across multiple data centers, yet their performance critically depends on effective leader management under wide-area network (WAN) dynamics. Legacy approaches fall short as they either ignore application-level factors or incur high switching overheads. This paper presents GeoLM, a lightweight, performance-oriented leader management framework. GeoLM formalizes a utility model that jointly captures network delays, node popularity, and read-write ratios, and integrates three mechanisms: (i) Target Selection to identify promising leaders, (ii) Switching Damping to bound oscillations and ensure stable leadership, and (iii) Leader Handover with log pre-synchronization to minimize downtime. GeoLM is implemented in ETCD-Raft and seamlessly extends existing protocols without altering log replication. Comprehensive evaluation-including trace-driven simulations with AWS latency traces and real-world deployments across multiple regions-demonstrates that GeoLM reduces average latency by up to 30.77%, tail latency by up to 49.75%, and improves throughput by up to 28% over baseline protocols (depending on the comparison). GeoLM further delivers consistently better performance than state-of-the-art protocols such as SwiftPaxos, CURP, and EPaxos, while maintaining strong consistency guarantees.

Packet losses significantly impact the user experience of content delivery network (CDN) services such as live streaming and data backup-and-archiving. However, our production network measurement studies show that the legacy loss recovery is far from satisfactory due to the wide-area loss characteristics (i.e., dynamics and burstiness) in the wild. In this paper, we propose a sender-side Adaptive ReTransmission scheme, ART, which minimizes the recovery time of lost packets with minimal redundancy cost. Distinguishing itself from forward-error-correction (FEC), which preemptively sends redundant data packets to prevent loss, ART functions as an automatic-repeat-request (ARQ) scheme. It applies redundancy specifically to lost packets instead of unlost packets, thereby addressing the characteristic patterns of wide-area losses in real-world scenarios. We implement ART upon QUIC protocol and evaluate it via both trace-driven emulation and real-world deployment. The results show that ART reduces up to 34% of flow completion time (FCT) for delay-sensitive transmissions, improves up to 26% of goodput for throughput-intensive transmissions, reduces 11.6% video playback rebuffering, and saves up to 90% of redundancy cost.