InfiniCache: Exploiting Ephemeral Serverless Functions to Build a Cost-Effective Memory Cache

TL;DR

InfiniCache leverages ephemeral serverless functions to create a cost-effective, elastic in-memory caching system that balances data availability, performance, and cost savings for large-object workloads.

Contribution

This paper introduces InfiniCache, a novel in-memory caching system built on serverless functions, combining erasure coding and intelligent control for improved cost and data availability.

Findings

Achieves 31-96X cost savings compared to AWS ElastiCache.

Provides 95.4% data availability within one hour.

Offers performance comparable to traditional in-memory caches.

Abstract

Internet-scale web applications are becoming increasingly storage-intensive and rely heavily on in-memory object caching to attain required I/O performance. We argue that the emerging serverless computing paradigm provides a well-suited, cost-effective platform for object caching. We present InfiniCache, a first-of-its-kind in-memory object caching system that is completely built and deployed atop ephemeral serverless functions. InfiniCache exploits and orchestrates serverless functions' memory resources to enable elastic pay-per-use caching. InfiniCache's design combines erasure coding, intelligent billed duration control, and an efficient data backup mechanism to maximize data availability and cost-effectiveness while balancing the risk of losing cached state and performance. We implement InfiniCache on AWS Lambda and show that it: (1) achieves 31 -- 96X tenant-side cost savings compared to AWS ElastiCache for a large-object-only production workload, (2) can effectively provide 95.4% data availability for each one hour window, and (3) enables comparative performance seen in a typical in-memory cache.