ClusterCATS makes certain that your Web applications remain available and running at optimum performance by intelligently managing the amount of HTTP traffic hitting your clustered servers. By setting load thresholds on each server in your cluster, you can control and manage your site's availability and performance. Many of your threshold configuration decisions hinge on your site's architecture and where the bulk of your processing resources need to be allocated.
During an HTTP redirection, ClusterCATS evaluates the cluster's state according to HTTP server state first, and then ColdFusion server load. This policy is the same in both centralized and distributed ClusterCATS configurations. In a centralized ClusterCATS cluster with all Web servers at one site, ClusterCATS only redirects if the server is busy or restricted.
For each cluster member, you configure two load thresholds:
By default, the Peak load threshold is 90% and the gradual redirection threshold is 10%. These default settings adequately handle HTTP traffic going across most Web sites. However, if your Web site is particularly processing intensive, you should lower both threshold settings to better accommodate the increased load.
If you want the server to be able to handle as much load as possible, set both threshold values close to one another. However, if you want redirection to occur well in advance of the server nearing its peak threshold, set the values farther apart so that there is a differential of at least 10% between the two threshold values.
This section shows you how to set the peak and gradual redirection load thresholds for ClusterCATS servers in the following sections:
The server's Properties dialog box appears:
ColdFusion reports its load data directly to ClusterCATS. Consequently, you can view the load on the ColdFusion servers at any time using the Server Load Monitor.
The Server Load dialog box appears and displays the current load status for each cluster member in the cluster you selected.
The load monitor shows three lines:
You can view and set threshold settings of an individual cluster member using the Server Load Monitor's visual display. To set or change threshold settings using this method, use your mouse to drag the Peak (red) and Gradual Redirection (yellow) threshold lines to their desired settings instead of entering numeric values in fields, as you do in the server Properties dialog box.
The Server Load dialog box appears:
As you move the line, the Peak load threshold percentage changes.
The Show Cluster page appears:
The Cluster Member List page appears, as the following figure shows. If you get an "Error: Server <cluster_member_name> could not be found" message, make sure you used the correct, fully-qualified server name and that the server is running.
The Connect To Server page appears:
The selected server's Server Properties page appears:
The Server Administration page appears for the selected server.