và chưa di chuyển đến một hệ thống cơ sở dữ liệu điều khiển. Khi SA, đó là công việc của bạn để khuyến khích các trang web đó để di chuyển đến một mô hình cơ sở dữ liệu theo định hướng càng sớm càng tốt. Ở mức QPS-thứ hai, chẳng hạn một máy chủ phải được quy mô như cơ sở dữ liệu bất kỳ | 696 Chapter 29 Web Services and have not yet migrated to a database-driven system. As the SA it is your job to encourage such sites to move to a database-driven model as early as possible. At QPS-second rates such a server must be scaled like any database with the usual database performance-tuning tools that are available. Multimedia Servers A multimedia server is primarily a web server that has content that includes media files such as video or audio. Media files are often very large and sometimes are accessed through some type of special client or browser to comply with digital rights management. When serving media files the underlying data storage and network bandwidth capabilities become more important. Media servers provide streaming-media support. Typically streaming media is simply using a web application on the server to deliver the media file using a protocol other than HTTP so that it can be viewed in real time. The server delivers a data stream to a special-purpose application. For example you might listen to an Internet radio station with a custom player or a proprietary audio client. Often one purpose of a media server application is to enforce copy protection or rights management. Another purpose is to control the delivery rate for the connection so that the data is displayed at the right speed if the web site does not allow the end user to simply download the media file. The application will usually buffer a few seconds of data so that it can compensate for delays. Streaming-media servers also provide fast-forward and rewind functions. When operating a media server that is transmitting many simultaneous streams it is important to consider the playback speed of the type of media you are serving when choosing the storage and network capabilities. In Chapter 25 we mention some characteristics of storage arrays that are optimized for dealing with very large files that are seldom updated. Consider memory and network bandwidth in particular since
