Mirror
Mirroring is a technique used to create a complete copy of an Internet resource such as a website, downloadable file, or database, in order to improve the experience of users who access the resource.
Websites that grow to be incredibly popular in multiple geographically separate areas can set up mirror websites hosted on servers all around the globe. That way, the traffic to each server is reduced and visitors are served up the website from a server that is much closer to them geographically. The result is that the website performs better for visitors all around the globe.
This technique of creating a duplicate copy of a website is called mirroring, and the resulting website is called a mirror site.
Mirroring is also commonly used to distribute popular downloadable files such as open source software. Mirroring downloadable files provides the same proximity benefits as are seen when a website is mirrored, with the added benefit that additional servers and network capacity are made available to handle the demanding process of allowing multiple users to download a resource simultaneously.
Frequently Asked Questions
What are the benefits of mirroring?
In most cases, a website or downloadable file is mirrored because the original server cannot keep up with the amount of traffic or download requests being made. However, there are also other potential benefits to mirroring depending on the situation. For example:
- When a website is undergoing a major overhaul or upgrade, a mirrored version of the site on a separate server can keep the original site live while work is being done on other servers.
- If there is concern about information being lost due to censorship or a server failure, a mirror in a geographically distant location will help protect against data loss and heavy-handed censorship.
- If a website is being replaced or removed, but it is desirable to keep a copy of the site available for historical purposes, a mirror site is a good way to do so.
- When a web server on the other side of the world is accessed, the distance that messages have to travel as well as the volume of traffic on the Internet can produce a slow experience. Mirroring a website or downloadable resource on servers located all around the globe will improve website performance and download speed for visitors around the globe.
Are all mirrors set up by the original website's administrators?
Many websites, especially open source projects such as PHP.net and Apache Web Server actively recruit new mirrors for their primary website or for downloadable files.
When someone with available server space volunteers to host a mirror, they do have to do some work setting up the mirrored resource, configuring the server, and maintaining the mirror. However, mirrored resources are usually set up in such a way that updates to the resource can be delivered to the mirror server automatically. As a result, it is entirely possible for a resource to be mirrored several times, but for only the original server to be actively managed by the website administrators while all of the mirrors are updated automatically when changes are made to the primary server.