DESIGN AND ANALYSIS OF CONTENT CACHING SYSTEMS

Caching is a simple yet powerful technique that has had a significant impact on improving the performance of various computer systems. From internet content delivery to CPUs, domain name systems, and database systems, caching has played a pivotal role in making these systems faster and more efficient. The basic idea behind caching is to store frequently accessed data locally, so that future requests for that data can be served more quickly. For example, a Content Delivery Network (CDN) like Akamai deploys thousands of edge caches across the globe, so that end-user requests can be served from a nearby cache, rather than a remote origin server, resulting in a significant reduction in latency. With billions of users accessing the internet every day to download various types of content such as videos, documents, images, web pages, and software, caching has become ubiquitous and critical to the functioning of the internet. In this thesis, we make several contributions to caching research by addressing key challenges related to content caching systems. Specifically, we improve the fault tolerance mechanism of a CDN cache cluster, develop tailored cache algorithms for different content types, and propose synthetic trace generation tools to evaluate cache performance in the absence of production traces. In the first part of this thesis, we identify a limitation in the state-of-the-art fault-tolerance mechanism used in a CDN cache cluster, which relies on object replication. We demonstrate that this approach is both inefficient and ineffective. To address this challenge, we develop a new fault-tolerance mechanism that leverages erasure codes, which we call C2DN (Coded-CDN). C2DN provides a more efficient and effective solution for fault-tolerance in CDN cache clusters. Specifically, we show that C2DN achieves an 11% lower byte miss ratio compared to object replication, demonstrating its superior efficiency. Additionally, C2DN eliminates unavailability-induced miss ratio spikes, resulting in a more effective approach to ...