Some probably have heard these three words, but what exactly this mean and why it’s needed?
Load balancing is the process where inbound IP traffic is distributed across multiple servers. Google uses it, you can see it if you nslookup google.com in Linux terminal or Windows cmd you get multiply IP witch are used by Google.com to balance server load. So if there is only one web server responding to all the incoming requests for website, the capacity of the web server may not be able to handle high volumes of incoming traffic and pages will load slowly as the users will have to wait until the web server process their requests. Image how many users use google.com and when server will slow down on processing request it eventually will cost the money or server dies, so its good idea too use multiply servers.
Graphically load balancing on servers looks something like this:
Picture from: http://www.tractionet.com/index.php?main_page=learn&articleid=16&zenid=54c5rcsvnavh7k2m0t39g25bn2
Usually there are two or more web servers in a load balancing scheme. In case one of the servers begins to get overloaded, the requests are forwarded to another server. Also load balancing is good against multiple forms of denial−of−service (DoS) attacks, since you have more servers needs more resources to kill all servers in one time. Also use can save money for instance not buying on mega expensive server you buy more middle level servers with greater combined power. Good thing also is that you want to make upgrades to server you need to shut them down but using multiply servers you services will always be accessible. Last but not least when when its comes to upgrade you can do it gradually and indefinitely.
References:http://content.websitegear.com/article/load_balance.htm http://www.wisegeek.com/what-is-load-balancing.htm http://www.tractionet.com/index.php?main_page=learn&articleid=16&zenid=54c5rcsvnavh7k2m0t39g25bn2 https://www.hasustorm.com/books/English/OReilly.Network.Warrior.June.2007.chm/130.server_load_balancing.html Book: Load balancing servers, firewalls, and caches / Chandra Kopparapu. ISBN 0-471-41550-2