google search engine architecture- how do so many concurrent users do a search on it

Question

With millions of users searching for so many things on google, yahoo and so on. How can the server handle so many concurrent searches? I have no clue as to how they made it so scalable. Any insight into their architecture would be welcomed.

Answer 1

One element, DNS load balancing.

There are plenty of resources on google architecture, this site has a nice list:

• http://highscalability.com/google-architecture

Answer 2

DNS Load Balancing is correct, but it is not really the full answer to the question. Google uses a multitude of techniques, including but not limited to the following:

• DNS Load Balancing (suggested)
• Clustering - as suggested, but note the following
  • clustered databases (the database storage and retrieval is spread over many machines)
  • clustered web services (analogous to DNSLB here)
  • An internally developed clustered/distributed filing system
• Highly optimised search indices and algorithms, making storage efficient and retrieval fast across the cluster
• Caching of requests (squid), responses (squid), databases (in memory, see shards in the above article)