Other Servers

Google, being the most popular Internet search engine (over 50% market share), requires large computational resources in order to provide their service. This article describes Google's technological infrastructure, as presented in the company's public announcements. more...

Home
Cables, Connectors
Filers, Load Balancers
Home Networking, Cable & DSL
Hubs
KVM Switch Boxes, Cables
Mainframe, DEC, VAX, AS/400
Network Interface Cards,...
Networking, Telecom Tools
Other Networking Equipment
Print Servers, Wired
Racks, Mounts & Patch Panels
Router Components, Memory
Routers, Wired
Security, Firewall, VPN
Server Components, Memory
Servers
Compaq
Custom, WhiteBox Servers
Dell
HP
IBM
Other Servers
Sun
Software
Software, Operating Systems
Storage Equipment, NAS, SAN
Switch Components, Memory
Switches
Telephone Systems, Telecom
UPS, Power Protection, APC
Wholesale Lots
Wireless Networking, WiFi
Workstation Components,...
Workstations, Terminals

Network topology

Google maintains an estimated 450,000 servers, arranged in racks located in clusters in cities around the world, with major centers in Mountain View, California; Virginia; Atlanta, Georgia; Dublin, Ireland; and a new facility constructed in 2006 in The Dalles, Oregon. When an attempt to connect to Google is made, Google's DNS servers perform load balancing to allow the user to access Google's content most rapidly. This is done by sending the user the IP address of a cluster that is not under heavy load, and is geographically proximate to them. Each cluster has a few thousand servers, and upon connection to a cluster further load balancing is performed by hardware in the cluster, in order to send the queries to the least loaded Web Server. This makes Google one of the biggest and most complex known Content Delivery Networks.

Racks are custom-made and contain 40 to 80 servers (20 to 40 1U servers on either side), new servers are 2U Rackmount systems. Each rack has a switch. Servers are connected via a 100 Mbit/s Ethernet link to the local switch. Switches are connected to core gigabit switch using one or two gigabit uplinks.

Main index

Since queries are composed of words, an inverted index of documents is required. Such an index allows obtaining a list of documents by a query word. The index is very large due to the number of documents stored in the servers, therefore it needs to be split up into "index shards". Each shard is hosted by a set of index servers. The load balancer decides which index server to query based on the availability of each server.

Server types

Google's server infrastructure is divided in several types, each assigned to a different purpose:

Google DNS Servers answer the DNS requests and serve as intelligent, worldwide load-balancer. They guess the data center nearest to the user to speed up all http requests.;

Google Web Servers coordinate the execution of queries sent by users, then format the result into an HTML page. The execution consists of sending queries to index servers, merging the results, computing their rank, retrieving a summary for each hit (using the document server), asking for suggestions from the spelling servers, and finally getting a list of advertisements from the ad server.;

Read more at Wikipedia.org