File, Database and I/O Systems Performance

有两种技术趋势强烈影响着I/O系统的设计和性能。首先，处理器能力，特别是对于单(或少数)芯片设计，正在非常迅速地增长，导致：(A)(几乎)I/O负载相应增加，(B)具有工作站(w/wo本地磁盘)、文件服务器和计算节点的分布式系统，以及(C)与提供相同总体性能的单处理器相比具有巨大性价比优势的多处理器。其次，磁盘存储密度正在快速增加，而磁盘性能却没有任何可比的提高。由于这些趋势，一些设计和优化问题变得极其重要：(A)由于I/O速率的增加和I/O系统对这些瓶颈的响应能力的降低，系统越来越容易受到I/O瓶颈的影响。(B)具有共享输入/输出设备和/或数据库的多处理器系统在引用、锁定和更新共享数据时越来越容易受到输入/输出瓶颈的影响。该项目继续研究与文件、I/O和数据库系统性能有关的一些主题。这些措施包括：(A)开发和分析分布式和分级系统中的磁盘缓存算法，同时考虑到一致性和性能。(B)研究磁盘缓存与磁盘条带化和日志结构文件系统相结合的效果。(C)分析和开发共享、分布式数据库系统的锁定算法。(D)设计、优化和实施将在加州大学伯克利分校建造的使用光盘的超大型海量存储系统中的分层和分布式文件迁移。这项工作在很大程度上依赖于实际的系统测量和轨迹驱动的仿真。

There are two technology trends strongly impacting the design and performance of I/O systems. First, processor power, especially for single (or few) chip designs, is increasing very rapidly, leading to: (a) (almost) corresponding increases in I/O load, (b) distributed systems with workstations (w/wo local disks), file servers and computation nodes, and (c) multiprocessors with enormous cost/performance advantages over uniprocessors providing the same aggregate performance. Second, disk storage densities are increasing rapidly without any comparable increase in disk performance. A number of design and optimization problems have become extremely important due to these trends: (a) Systems are becoming increasingly susceptible to I/O bottlenecks due to increasing I/O rates and the less quickly in creasing ability of the I/O system to respond to them. (b) Multiprocessor systems with shared I/O devices and/or databases are increasingly susceptible to I/O bottlenecks in referencing, locking and updating shared data. This project continues research on a number of topics relating to file, I/O and database system performance. These include: (a) Development and analysis of algorithms for disk caching in distributed and hierarchical systems, taking into account both consistency and performance. (b) Studies of the effect of disk caching in conjunction with disk striping and log structured file systems. (c) Analysis and development of locking algorithms for shared, distributed database systems. (d) Design, optimization and implementation of hierarchical and distributed file migration in a very large mass storage systems using optical disks to be built at UC Berkeley. The work relies heavily on actual system measurement and trace driven simulation.