Popular Internet databases, such as AltaVista, generate a great deal of traffic. One way to dissipate the traffic and provide backup copies of the database is to establish mirror sites. By placing these mirrors around the globe, the intent isto divide the traffic regionally. Theoretically, avoiding trans-oceanic connections should result in faster response time. The principle of multiple mirror sites is to provide exact duplicate copies of the database accessible at a variety of access points around the world. In the pre-Web days of the Internet, popular FTP archives often had several mirror sites. One difficulty with mirror sites is maintaining the same database at multiple locations. Ideally, every time the main database is updated, all the mirrors are as well. With dynamically and frequently changing databases that are also extremely large, the problem requires careful planning and coordination. Alternatively, mirror sites might provide additional regional content. AltaVista currently has five international mirror sites: For the searcher, the questions to be answered include: Are the databases all the same? Are the search features identical? And are there any advantages to using one of the mirror sites.
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