An article was recently posted on notes.net regarding how to achieve high availability with iNotes. In the article, Domino clustering, the iNotes redirector database, and a high end dedicated load balancer appliance is used to provide high web availability. If you are fortunate to have a load balancer appliance in your environment, be sure to take advantage of it for your Domino web environment. However, several years ago (in 2005 to be precise) when implementing a clustered iNotes-only environment, we did not have such a device available, nor the budget for it. So what do you do in a pinch? You get creative!
We installed two Windows 2000 Advanced servers, each running Websphere Edge Server. We then installed two more Windows 2000 servers, each running Domino, with a customized version of the redirect database. These servers were clustered to each other. Websphere Edge Server was configured to load balance and provide failover for the redirect servers as well as the web servers on the back end.
Remarkably, this implementation is still in place five years later. And it WORKS! The two redirect servers act as the central login point for all web authentications for this particular population of iNotes user.
The two Websphere Edge Servers provide redundancy for each other, as that is a service that Edge Server can provide. And don’t get panicky about the Websphere name. This is not as difficult to install as Websphere Application Server or Websphere Portal. You do need a good understanding of networking – especially if you are going to use NAT or the Cache Proxy service that is available via the Edge Server. Websphere Edge Server components are available via the Passport Advantage site.
And because we include several Domino attributes including, mail file, and Domino server name in our LDAP directory (using the magic of Tivoli Directory Integrator!), the redirect servers act as the central authentication point for all Domino servers supported by this configuration. Users don’t have to remember a specific server name, or that in the case of a server outage that they have to go to the cluster mate. The combination of Websphere Edge Server and iNotes redirect allows them to continue to use iNotes almost unaware that a server has failed! Which of course is always a goal of Domino Administrators right? Happy users!