Impliance: A Next Generation Information Management Appliance

ably successful in building a large market and adapting to the changes of the last three decades, its impact on the broader market of information management is surprisingly limited. If we were to design an information management system from scratch, based upon today's requirements and hardware capabilities, would it look anything like today's database systems?" In this paper, we introduce Impliance, a next-generation information management system consisting of hardware and software components integrated to form an easy-to-administer appliance that can store, retrieve, and analyze all types of structured, semi-structured, and unstructured information. We first summarize the trends that will shape information management for the foreseeable future. Those trends imply three major requirements for Impliance: (1) to be able to store, manage, and uniformly query all data, not just structured records; (2) to be able to scale out as the volume of this data grows; and (3) to be simple and robust in operation. We then describe four key ideas that are uniquely combined in Impliance to address these requirements, namely the ideas of: (a) integrating software and off-the-shelf hardware into a generic information appliance; (b) automatically discovering, organizing, and managing all data - unstructured as well as structured - in a uniform way; (c) achieving scale-out by exploiting simple, massive parallel processing, and (d) virtualizing compute and storage resources to unify, simplify, and streamline the management of Impliance. Impliance is an ambitious, long-term effort to define simpler, more robust, and more scalable information systems for tomorrow's enterprises.Comment: This article is published under a Creative Commons License Agreement (http://creativecommons.org/licenses/by/2.5/.) You may copy, distribute, display, and perform the work, make derivative works and make commercial use of the work, but, you must attribute the work to the author and CIDR 2007. 3rd Biennial Conference on Innovative Data Systems Research (CIDR) January 710, 2007, Asilomar, California, US

104 New-Value Logging in the Echo Replicated File System

The charter of SRC is to advance both the state of knowledge and the state of the art in computer systems. From our establishment in 1984, we have performed basic and applied research to support Digital’s business objectives. Our current work includes exploring distributed personal computing on multiple platforms, networking, programming technology, system modelling and management techniques, and selected applications. Our strategy is to test the technical and practical value of our ideas by building hardware and software prototypes and using them as daily tools. Interesting systems are too complex to be evaluated solely in the abstract; extended use allows us to investigate their properties in depth. This experience is useful in the short term in refining our designs, and invaluable in the long term in advancing our knowledge. Most of the major advances in information systems have come through this strategy, including personal computing, distributed systems, and the Internet. We also perform complementary work of a more mathematical flavor. Some of it is in established fields of theoretical computer science, such as the analysis of algorithms, computational geometry, and logics of programming. Other work explores new ground motivated by problems that arise in our systems research. We have a strong commitment to communicating our results; exposing and testing our ideas in the research and development communities leads to improved understanding. Our research report series supplements publication in professional journals and conferences. We seek users for our prototype systems among those with whom we have common interests, and we encourage collaboration with university researchers

Evolving the Unix system interface to support multithreaded programs

Allowing multiple threads to execute within the same address space makes it easier to write programs that deal with related asynchronous activities and that execute faster on shared-memory multiprocessors. Supporting multiple threads places new constraints on the design of operating system interfaces. We present several guidelines for designing or redesigning interfaces for multithreaded clients. We show how these guidelines were used to design an interface to UNIX1-compatible file and process management facilities in the Topaz operating system. Two implementations of this interface are in everyday use: a native one for the Firefly multiprocessor, and a layered one running within a UNIX process. 1

Availability in the Echo File System

This paper describes the aspects of the Echo design that are related to providing high availability. These aspects include the provision of redundant components (replicated disks and backup servers), the replication of information, and recovery from failures. Further, we discuss some less obvious mechanisms needed for providing truly high availability: load control, dynamic reconfiguration of the system, and the detection and reporting of faults. Finally, we discuss some of the impact of our availability mechanisms on application software

An Algorithm for Data Replication

Replication is an important technique for increasing computer system availability. In this paper, we present an algorithm for replicating stored data on multiple server machines. The algorithm organizes the replicated servers in a master/slaves scheme, with one master election being performed at the beginning of each service period. The status of each replica is summarized by a set of monotonically increasing epoch variables. Examining the epoch variables of a majority of the replicas reveals which replicas have up-to-date data. The set of replicas can be changed dynamically. Replicas that have been off-line can be brought up to date in background, and witness replicas, which store the epoch variables but not the data, can participate in the majority voting. The algorithm does not require distributed atomic transactions. The algorithm also permits client machines to cache copies of data, with strict cache consistency being ensured by having the replicated servers keep track of which cl..