Mirror (computing)

A mirror (English mirror), often just referred to as simply " mirror" in computer networks maintains an exact copy of a data set.

Central servers of large projects often do not have the data transfer rate to provide their services to all interested parties within a reasonable time. For this reason, the data is "mirrored" on other servers, so it is a 1:1 image is created and made available to interested parties available there.

Because synchronization is usually done asynchronously, this "mirror image " is not always up to date, but is an important method that will keep the Internet Data available at all times. For example, the Domain Name System is essentially based on the "flipping " of the servers known data. The update is done not in real time but after predetermined time intervals.

For example, there are of all Linux distributions on multiple servers on the Internet copies. In this way the data is stored on different computers for download, and you reach a distribution of resources in accessing high traffic data. The respective mirror server, for example, every night at 3 clock with the current data source is synchronized ( usually with rsync ).

Volksetymologie

An Urban Legend called Linus Torvalds as the author of the following award: "Backups are for wimps. Real men upload Their stuff on the internet and let the world mirror it. " As a comment on the fact that the loss of its source code to the Linux kernel would be intercepted by the fact that these are mirrored by several computers.

This saying, however, is neither guaranteed as the derivation of the term mirror from the book Alice in Wonderland or the follow-up book Through the Looking - Glass by Lewis Carroll.

Example with Wget

With the free command line tool wget websites can use the option - are mirrored mirror or -m.