The new vision of cloud computing demands scalable, available and autonomic software platforms in order to deploy applications and services accessible anywhere and anytime. Multi-tier architectures are an important building block for many applications that are deployed in the cloud. This paper presents a novel caching and replication infrastructure that facilitates the scalable and elastic deployment of multi-tier architectures. Our Elastic SI-Cache is a novel multi-version cache that attains high performance and consistency in multi-tier systems. In contrast to most existing caches, Elastic SI-Cache provides snapshot isolation coherently across all tiers. Furthermore, Elastic SI-Cache supports scalable replication of the different tiers where replicas can be added or removed dynamically as needed, making the cache amenable for cloud computing environments. Elastic SI-Cache has been implemented and integrated into an open source JEE application server and its performance evaluated with the industrial benchmark SPECjAppServer.