CD-Raft: Reducing the Latency of Distributed Consensus in Cross-Domain Sites
This addresses the latency challenge in cross-domain consensus for systems like data centers handling AI workloads, but it is incremental as it builds on the existing Raft protocol.
The paper tackles the problem of high latency in distributed consensus across cross-domain sites, which is critical for AI computation loads, and presents CD-Raft, an optimized Raft protocol that reduces average latency by 32.90% and tail latency by 49.24% compared to classic Raft.
Today's massive AI computation loads push heavy data synchronization across sites, i.e., nodes in data centers. Any reduction in such consensus latency can significantly improve the overall performance of desired systems. This consensus challenge explosively peaks at cross-domain sites. In this paper, we proposed CD-Raft to address the cross-domain latency challenge, an optimized Raft protocol for strong consistency in cross-domain sites. CD-Raft can significantly reduce consensus latency by optimizing cross-domain round-trip time (RTT) for reads and writes, as well as carefully positioning the leader node. We verified the correctness of CD-Raft in a formal specification using the TLA+ specification, guaranteeing the strong consistency across sites. We have prototyped CD-Raft and evaluated it using the YCSB benchmark. Empirical results show that compared to the classic Raft, CD-Raft reduces the average latency by 32.90% and (99th percentile) tail latency by 49.24% for renown traces across multiple sites.