Virtual Machine Snapshots with FaaSnap

Virtual machine (VM) snapshots are a promising way to solve the cold start problem in serverless computing (FaaS). Serverless platforms can avoid the slow VM booting and initialization by using on-disk snapshots. However, due to the speed requirements associated with guest memory accesses and the unpredictable nature of FaaS applications, loading snapshots to memory can be challenging.

Recently, PhD student Lixiang Ao, along with George Porter and Geoffrey Voelker, published FaaSnap: FaaS Made Fast Using Snapshot-based VMs, which tackles the snapshot loading problem.

FaaSnap uses a set of complimentary optimizations, including concurrent paging, per-region memory mapping and compact loading set files, to improve snapshot loading performance. FaaSnap improves end-to-end performance for on-disk snapshots by up to 3.5 times and is only 3.5% slower than snapshots cached in memory. This paper is being presented this week at EuroSys 2022