OctaGate DNS is a load balancing solution with failover that scales extremely well and has no single point of failure.

Many other load balancing solutions a) introduce a single point of failure, and b) introduce a new data bottleneck (the load balancer). OctaGate DNS introduces no bottlenecks, and has no single point of failure.

OctaGate DNS can co-exist with other load balancing solutions, removing their single points of failure and removing their bottlenecks. For instance, two distinct server farms with load balancing switches can still generate problems if one of the load balancing switches dies. In that situation, OctaGate DNS would route all users to the data center that's still working.

To use OctaGate DNS you will require

• At least one server that can run the OctaGate DNS software - preferably two or more on separate computers. The OctaGate DNS server can run on any Windows NT machine and even co-exist with other servers (Web, Mail, etc). The OctaGate DNS license allows you to run OctaGate DNS for on servers.
• All your servers that should be load balanced must have at least one external IP number that they can be reached at. OctaGate DNS can not load balance over servers that can't be individually reached.

OctaGate DNS does not require that you install any additional software on your servers.

Webopedia defines Load Balancing as;

"Distributing processing and communications activity evenly across a computer network so that no single device is overwhelmed. Load balancing is especially important for networks where it's difficult to predict the number of requests that will be issued to a server. Busy Web sites typically employ two or more Web servers in a load balancing scheme. If one server starts to get swamped, requests are forwarded to another server with more capacity. Load balancing can also refer to the communications channels themselves."

Failover is defined as;

"A backup operation that automatically switches to a standby database, server or network if the primary system fails or is temporarily shut down for servicing. Failover is an important fault tolerance function of mission-critical systems that rely on constant accessibility. Failover automatically and transparently to the user redirects requests from the failed or down system to the backup system that mimics the operations of the primary system.

When users try to access your servers (web, email, db etc) they initially ask a DNS server to give them an appropriate IP number for the server. The DNS server will return one or several IP numbers that match one or several of the requested servers. For instance, requesting www.example.com might return 10.0.0.2. The users will the connect to the supplied IP number, never knowing that there might in fact be many servers that all help built the web site.

DNS load balancing simply makes sure that as a request for a server is made, the load balancer returns the most appropriate server. Most appropriate means that it's a correctly functioning server with low relative load. It might even mean (a possible future addition to OctaGate DNS) a server from a server farm that's relatively close to the user - cutting down on internet overhead.

Most DNS "load balancing" solutions use a technique called Round Robin which isn't load balancing at all, merely load sharing and it offers no failover. If one of four server dies, on in four requests will return an invalid server! Also, if one server is relatively speaking much stronger than your other servers, the lowest common denominator will prevail if you use Round Robin.

OctaGate DNS will allow you to load balance based on server capacity. If you state that server X is three times stronger than server Y, it's three times more likely to be handed a request.

The concept of server capacity / strength is somewhat complex. If you have three web servers and one doubles as an FTP server, you might want to give it a lower capacity rating to compensate for the FTP load.

Also, if you have different data centers, you might want to assign capacity based on their relative internet capacity. Say you have three computers at location A and three computers at location B. If location A has a higher internet capacity than location B, you should assign the servers at location A a higher capacity, since they would be able to handle a larger load.

Please note that OctaGate DNS is NOT a DNS cache. A DNS cache is a piece of software that you install to allow your users to have quicker access to DNS data. Instead of contacting outside DNS servers, they'll all contact your DNS cache. However, all DNS "best practices" strongly suggest that authoritative DNS servers should never also perform DNS caching.

Please see The importance of separating DNS caches from DNS servers for a detailed explanation.

We suggest that if you need a DNS cache, you install an additional piece of software on another server, to take care of those needs.

OctaGate DNS is load balancing solution with failover, that's easy to deploy and can scale to any network size. All very large web sites use a form of DNS load balancing - typically simple Round Robin, which lacks failover and true load balancing.