IIS modifies queue Length (IIS6+IIS7)

Internet Information Services (IIS) limits the maximum number of application pool requests that can wait in a queue at any given time. If this limit is reached, all new requests will be rejected, and the user will receive the error message "503– Service Unavailable". By default, IIS sets the queue length to 1,000 requests. The default value may be too low because if the queue length is 1,000,communicator Web Access (R2 release), only about 650 concurrent users will be processed, and then new users will start to be rejected.

To help ensure the availability of a Communicator Web Access service, we recommend that you set the IIS queue Length value to 1.5 times times the expected maximum number of users. For example, assume that you expect a maximum of 2,000 users to log on to Communicator Web Access at a given time. In this case, the queue length should be set to 3,000 (that is, 1.5 times times for 2,000 users). In addition, if the server is running on Windows Server 2008, you need to configure the Appconcurrentrequestlimit setting to support more than 5,000 connections.

Change the queue Length setting in IIS 7.0

1. Click Start, point to Administrative Tools, and then click Internet Information Services (IIS) Manager.

2. In IIS Manager, expand the name of the IIS server, and then click Application Pools.

3. In the Application Pools pane, right-click the Communicator Web Access application pool, and then click Advanced Settings.

4. In the Advanced Settings dialog box, under General , click Queue Length, and then type a value that is 1.5 times times the maximum number of concurrent users in a Communicator Web Access deployment.

5. Click OK.

Change the queue Length setting in IIS 6.0

1. Click Start, click All Programs, point to Administrative Tools, and then click Internet Information Services (IIS) Manager.

2. In IIS Manager, expand the Sites node, right-click the Communicator Web Access application pool, and then click Properties.

3. In the Properties dialog box, click the Performance tab.

4. Under request queue limit , click Core Request queue limit to (number of requests), and then type a value that is 1.5 times times the maximum number of concurrent users in a Communicator Web Access deployment.

5. Click OK.

IIS modifies queue Length (IIS6+IIS7)