One of the surprising thing about connection sites is that , in sure cases , a very small automobile can handle a huge number of visitors . For good example , imagine that you have a unsubdivided Web site contain a number of staticpages(in this case , " static " means that everybody sees the same interpretation of any page when they take in it ) . If you took a normal 500MHz Celeron auto running Windows NT or Linux , loaded theApache Web serveron it , and connected this machine to the Internet with a T3 line ( 45 million bit per indorsement ) , you could handle hundreds of thousands of visitors per Clarence Shepard Day Jr. . Many ISPs will rent you a dedicated - machine configuration like this for $ 1,000 or less per month . This constellation will work great unless :
Since most of the large Web sites fit all of these conditions , they need significantly magnanimous infrastructures .
There are three main strategies for manage the load :
When you visit a site that has a unlike URL every sentence you chaffer ( for examplewww1.xyz.com , www2.xyz.com , www3.xyz.com , etc . ) , then you know that the web site is using the second approach at the front end . Typically the website will have an array of stand - alone machine that are each go connection server software . They all have access to an identical transcript of the pages for the site . The incoming requests for pages are spread across all of the auto in one of two ways :
The advantage of this superfluous access is that the failure of any one motorcar does not cause a problem – the other machine pick up the payload . It is also gentle to add capacity in an incremental elbow room . The disadvantage is that these political machine will still have to babble to some sort of centralized database if there is any dealing processing going on .
Microsoft’sTerraServertakes the " single large machine " glide path . Terraserver store several TB of planet imaging data and handles millions of requests for this information . The site uses vast enterprise - division machines to handle the incumbrance . For example , a undivided Digital AlphaServer 8400 used at TerraServer has eight 440 MHz 64 - bit processor and 10 GB of mistake checked and correct RAM . Seethe engineering science descriptionfor some truly impressive specification !
