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Clustering and Load Balancing
While servers today are very reliable and are generally up and running
over 99% of the time, servers can still go down. Businesses with
mission critical web sites often want failover protection in case a
problem occurs on a live server. Additionally, high traffic web
sites usually require two or more servers just to handle the traffic.
Below is a brief primer on the major types of redundant server
configurations. Please contact sales
to obtain a custom proposal for your individual needs.
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The simplest
and least expensive way to create failover protection is to have two
servers as shown to the right. One server is active and one is a hot
backup. The DNS server (there are actually two or more DNS
servers) will detect if the live server is down and, if so, route
traffic to the backup server. In reality, both servers can be live
and the DNS server can divide traffic between the two as long as both
are running. You can have more than two servers as well.
Advantages: Inexpensive; easy to
set up; no single point of failure (there are at least 2 DNS servers)
Disadvantages: If a server
goes down, some traffic might still get routed to the down server for a few
minutes as there is some latency (though minimal). If
routing traffic to two or more live servers, the load balancing is not
precise. |
Go to
Clustering page 2 |
