AltaVista's Imperfect Mirrors
From The Search Engine Report
March 31, 1998
AltaVista maintains a network of mirror sites outside the United States. These are meant to be identical copies of the main AltaVista index, but in fact, all but one of the mirrors list fewer pages than the main service.
AltaVista confirmed the problem and said that it is working on it, but that it could not release more details on the situation, at the moment.
It is likely that the mirror sites don't yet have the hardware structure of the main site, which was upgraded late last year when the index was increased from 30 million to 100 million web pages.
Some spot-checking of URL counts seems to indicate that the mirrors have about one-quarter to one-third the pages of the main index.
This is important to search engine users outside the US. Mirrors may provide a slightly faster response, due to their closer physical proximity, but they are not as comprehensive as the main service. Related to this, they will display substantially different results than the main index.
AltaVista's Canadian mirror is the exception. Recently launched, the mirror includes 12 million more Canadian web pages than the main service contains. Canadians, and those looking for information about Canada, should certainly compare AltaVista Canada to the main service, to see if the extra pages produce better results.
As a reminder, there is no need to submit web sites to each of the mirrors. A submission to any of them simply causes the California-based spider to visit a site and add pages to the main index there. This index is then copied and sent to the mirrors.
AltaVista Search Network
Lists all the mirror sites.
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