DoubleTrack: Fault-Tolerant Stateful Serverless Computing with Asynchronous Shared Logs

Logging-based fault-tolerant methods have recently been widely used in serverless computing, which can provide exactly-once execution semantics for stateless functions. However, this would also introduce considerable system overhead in serverless platforms, especially for the function workflow scenarios. How to build an efficient fault-tolerant logging system for latency-sensitive stateful functions is still challenging. We find the prior synchronous logging design causing the workflow block on waiting for every log request, hinders the performance of workflow execution. In this paper, we present DoubleTrack, a serverless runtime system for fault-tolerant workflows. The key of DoubleTrack is the asynchronous shared log, which decouples fault-tolerant logging and workflow execution, thus mitigating the overhead of synchronous logging. Our evaluation with real-world workloads shows that compared to the synchronous logging approach, DoubleTrack achieves up to 45.8% end-to-end latency and 46.5% logging overhead reduction.