Q. What is the Windows System Resource Manager (WSRM)?

A. Available only for Windows Server 2003, Datacenter Edition, and Windows Server 2003, Enterprise Edition, WSRM is a component that's used to throttle CPU and memory usage on the servers on which it's installed. WSRM can be useful when you want to run multiple applications on a server while ensuring that no application consumes more than its fair share of resources, which could impede other applications' performance. WSRM lets you place caps on a process or user level to make sure that all processes have the required resources.

WSRM uses "soft" caps, which means that although each process is limited to a specific percentage of CPU utilization and amount of memory, a process can exceed the limit if no other process is competing for the resource. Let's say I've defined caps for three applications:

1. Application 1: 30 percent of CPU
2. Application 2: 50 percent of CPU
3. Application 3: 20 percent of CPU

If applications 2 and 3 each used 10 percent of the CPU and application 1 required more than its 30 percent allocation, WSRM would give application 1 the additional amount that it required, up to 80 percent of the total CPU. However, if one of the other applications later required more CPU, WSRM would grant the other application the amount of CPU it requested, up to its limit.

WSRM is supplied on the Windows 2003 Datacenter and Windows 2003 Enterprise CD-ROMs. You can also download WSRM at http://www.microsoft.com/windowsserver2003/downloads/wsrm.mspx.

Q. How do I specify a new process for Windows System Resource Manager (WSRM) to manage?

A. Before you can tell WSRM to impose CPU and memory restrictions on a process, you must define the process in WSRM by specifying matching criteria. Here's how to do this:

1. Start the Microsoft Management Console (MMC) Windows Server Resource Manager snap-in (Start, Programs, Administrative Tools, Windows Server Resource Manager).
2. Right-click Process Matching Criteria and select New Process Matching Criteria.
3. Give the matching criteria a name (e.g., the application's name), then click Add.
4. If the application is currently running, select Running Process from the drop-down list, then click Select and select the process.
5. The path of the selected process will be added. Click OK to close the dialog boxes.

You've now defined your application as a process to which WSRM can assign resources.

Q. How do I create a resource-allocation policy?

A. You use a resource-allocation policy in Windows System Resource Manager (WSRM) to assign soft CPU and memory caps to processes you've identified through process-matching criteria, as I explain in the FAQs "What's Windows System Resource Manager (WSRM?)" and "How do I specify a new process for Windows System Resource Manager (WSRM) to manage?". To allocate resources to processes you've defined, you must create a resource-allocation policy by performing these steps:

1. Start the Microsoft Management Console (MMC) Windows Server Resource Manager snap-in (Start, Programs, Administrative Tools, Windows Server Resource Manager).
2. Right-click Resource Allocation Policies and select New Resource Allocation Policy.
3. Enter a name for the policy--for example, Daytime.
4. Click Add to add processes for which WSRM should allocate resources. You'll see the dialog box In the Process Matching Criteria column, select the process for which you want to set limits, then enter the maximum amount of CPU you want to allocate to that process. You can also set memory limitations by selecting the Dependencies tab. Repeat this addition for each process whose resources you want to limit.
5. Click OK to close the dialog boxes.

You now have a resource-allocation policy that sets the soft caps for processes that are defined on the system.

Q. How can I activate a resource-allocation policy?

A. To activate a resource-allocation policy that you've defined in Windows System Resource Manager (WSRM), in the Microsoft Management Console (MMC) Windows Server Resource Manager snap-in, right-click the resource-allocation policy and select Set as Managing Policy from the context menu. The resource-allocation policy entry in the treeview pane will now have "[Manage]" next to it.

To make the resource-allocation policy active, you need to ensure that WSRM is managing the system. To do so, in the Windows Server Resource Manager snap-in's treeview pane, right-click Windows System Resource Manager and select Properties. The WSRM Managing State should be set to Running; if the state shows another setting, right-click the Windows System Resource Manager entry and select Start Managing from the context menu.

Q. Why can't clients view a Web site that I'm hosting on a Windows XP Service Pack 2 system?

A. XP SP2 includes the new Windows Firewall, which blocks inbound requests to port 80 (HTTP) and is enabled by default. To let clients access an XP SP2 Web host, perform these steps on the XP SP2 host:

1. Run firewall.cpl (Start, Run, firewall.cpl) to configure the firewall.
2. Select the Exceptions tab.
3. Click Add Port.
4. Enter HTTP for the name and 80 for the port.
5. Click OK.

If the XP SP2 Web host also serves HTTP Secure (HTTPS) Web pages, repeat these steps and enter HTTPS for the name and 443 for the port.