the key princlipes of large scall website architecture

now let focus on the architecture principles of web-based project. how to design the best software, i think the ideal architecture  must  meet the following basic features:

1 availability: the  uptime of a website is absolutely critical . it   must be constantly available  and is 24 /7 running . for example  : the large scale online retail website , even just  few minutes are unavailable ,  the servers break down ,it will be a disaster for the company which will let company  lose thousands or  millions dollars .so designing a high available system.  there are a lot of careful consideration ,it should be a redundancy backup for key components . if one of the them break down ,it must  be carry a recovery immediately.

2 consistent: the system must keep the data to be  consistent.whenever and whatever the users operate on the system.it should be always consistent.

3 management :the system must be extensible and maintainable .it means when  new functions  are added ,it can not cause a lot of modifications and even cause other function break down.it should be easy to blend in. and the codes better to readable and for others developers take part in without much barriers.

4 performance: the quick response from website has become a critical factor of a website.the speed of website affect usages and user satisfactory

5 cost: the cost of consideration is also important.

6 scalability :the scale of the website is one of aspect of it