Reset Runtime Statistics
Resets the runtime statistics immediately.
Make Server Available
Makes the selected server appear Available so that traffic can be routed to the server. This action is enabled only if the selected server is Unavailable or Drain.
Make Server Unavailable Gracefully
Makes the selected server appear Unavailable so that new traffic cannot be routed to the server. Pre-existing requests will complete successfully. This action is enabled only if the selected server is Available.
Make Server Unavailable Immediately
Makes the selected server appear Unavailable so that new traffic cannot be routed to the server. Pre-existing requests are terminated immediately. This action is enabled only if the selected server is Available.
Disallow New Connections
Makes the selected server refuse new connections to the server. Pre-existing requests will complete successfully. This action applies the host name affinity session and subsequent requests from the affinitized clients will continue to be routed to affinitized servers. This action is enabled only if the selected server is Available.
Similar to any cluster or load balancing technology, ARR allows administrators to “drain” a server, that is, prevent it from accepting new connections in order to perform maintenance on that server or some other task without affecting end user.
This is done in ARR generally by using the Make Server Unavailable Gracefully option. However, if you are using affinity, you can use the Disallow New Connections option instead. This option is more meaningful when the client affinity feature is in use, because ARR will honor the existing sessions when disallowing new connections. That is, when a client is affinitized to the server that is disallowing new connections, the client will continue to be routed to the same server and, therefore, there is no impact on the client. However, no new clients will be routed to the server that is disallowing new connections.
To use this option:
- Select the server farm, Exchange – OWA in this scenario;
- The following icons are shown:
Figure 3.14: Farm Configuration and Management Options
- Double-click Monitoring and Management;
- Right-click select the server you want to drain and click on Disallow New Connections:
Figure 3.15: Click on Disallow New Connections
- In the confirmation dialog box, click Yes:
Figure 3.16: Click Yes to Confirm
You can now refresh the Monitoring and Management dashboard and check the runtime statistics to ensure new connections are not being routed to the server that is disallowing new connections.
If you are using affinity and want to verify this, remove the cookie set by ARR by closing and restarting the browser.
Send several requests to the ARR server and refresh the dashboard in IIS Manager. Verify that the runtime statistics are changing only for the servers that are Available. More specifically, verify that the runtime statistics for the server that is disallowing new connections have not changed. You may want to send additional requests and refresh the dashboard as needed.
In this article we finished configuring Application Request Routing to publish Outlook Web App out to the Internet. In the next final article, we will see how to monitor servers in the farm and how to troubleshoot Application Request Routing.
If you would like to read the other parts in this article series please go to: