TransCom: a virtual disk-based cloud computing platform for heterogeneous services

PublishedJournal ArticleThis paper presents the design, implementation, and evaluation of TransCom, a virtual disk (Vdisk) based cloud computing platform that supports heterogeneous services of operating systems (OSes) and their applications in enterprise environments. In TransCom, clients store all data and software, including OS and application software, on Vdisks that correspond to disk images located on centralized servers, while computing tasks are carried out by the clients. Users can choose to boot any client for using the desired OS, including Windows, and access software and data services from Vdisks as usual without consideration of any other tasks, such as installation, maintenance, and management. By centralizing storage yet distributing computing tasks, TransCom can greatly reduce the potential system maintenance and management costs. We have implemented a multi-platform TransCom prototype that supports both Windows and Linux services. The extensive evaluation based on both test-bed experiments and real-usage experiments has demonstrated that TransCom is a feasible, scalable, and efficient solution for successful real-world use. © 2004-2012 IEEE

Enabling event-triggered data plane monitoring

We propose a push-based approach to network monitoring that allows the detection, within the dataplane, of traffic aggregates. Notifications from the switch to the controller are sent only if required, avoiding the transmission or processing of unnecessary data. Furthermore, the dataplane iteratively refines the responsible IP prefixes, allowing the controller to receive information with a flexible granularity. We implemented our solution, Elastic Trie, in P4 and for two different FPGA devices. We evaluated it with packet traces from an ISP backbone. Our approach can spot changes in the traffic patterns and detect (with 95% of accuracy) either hierarchical heavy hitters with less than 8KB or superspreaders with less than 300KB of memory, respectively. Additionally, it reduces controller-dataplane communication overheads by up to two orders of magnitude with respect to state-of-the-art solutions

Locality in search engine queries and its implications for caching

Caching is a popular technique for reducing both server load and user response time in distributed systems. In this paper, we are interested in the question of whether caching might be effective for search engines as well. We study two real search engine traces by examining query locality and its implications for caching. Our trace analysis results show that: (1) Queries have significant locality, with query frequency following a Zipf distribution. Very popular queries are shared among different users and can be cached at servers or proxies, while 16 % to 22% of the queries are from the same users and should be cached at the user side. Multiple-word queries are shared less and should be cached mainly at the user side. (2) If caching is to be done at the user side, short-term caching for hours will be enough to cover query temporal locality, while server/proxy caching should be based on longer periods such as days. (3) Most users have small lexicons when submitting queries. Frequent users who submit many search requests tend to reuse a small subset of words to form queries. Thus, with proxy or user side caching, prefetching based on user lexicon looks promising

Locality in Search Engine Queries and Its Implications for Caching

Caching is a popular technique for reducing both server load and user response time in distributed systems. In this paper, we consider the question of whether caching might be effective for search engines as well. We study two real search engine traces by examining query locality and its implications for caching. Our trace analysis results show that: (1) Queries have significant locality, with query frequency following a Zipf distribution. Very popular queries are shared among different users and can be cached at servers or proxies, while 16% to 22% of the queries are from the same users and should be cached at the user side. Multiple-word queries are shared less and should be cached mainly at the user side. (2) If caching is to be done at the user side, short-term caching for hours will be enough to cover query temporal locality, while server/proxy caching should use longer periods, such as days. (3) Most users have small lexicons when submitting queries. Frequent users who submit many search requests tend to reuse a small subset of words to form queries. Thus, with proxy or user side caching, prefetching based on user lexicon looks promising

Eleventh IEEE Symposium on High Performance Distibuted Computing, Aug 2002, Edinburgh, Scotland, pp. 321–330 A Secure Distributed Search System

This paper presents the design, implementation and evaluation of Mingle, a secure distributed search system. Each participating host runs a Mingle server, which maintains an inverted index of the local file system. Users initiate peerto-pee