Manual Chapter : Implementing Health and Performance Monitoring

Applies To:

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  • 12.1.6, 12.1.5, 12.1.4, 12.1.3, 12.1.2, 12.1.1, 12.1.0
Manual Chapter

Implementing Health and Performance Monitoring

Overview: Health and performance monitoring

You can set up the BIG-IP® system to monitor the health or performance of certain nodes or servers that are members of a load balancing pool. Monitors verify connections on pool members and nodes. A monitor can be either a health monitor or a performance monitor, designed to check the status of a pool, pool member, or node on an ongoing basis, at a set interval. If a pool member or node being checked does not respond within a specified timeout period, or the status of a pool member or node indicates that performance is degraded, the BIG-IP system can redirect the traffic to another pool member or node.

Some monitors are included as part of the BIG-IP system, while other monitors are user-created. Monitors that the BIG-IP system provides are called pre-configured monitors. User-created monitors are called custom monitors.

Before configuring and using monitors, it is helpful to understand some basic concepts regarding monitor types, monitor settings, and monitor implementation.

Monitor types
Every monitor, whether pre-configured or custom, is a certain type of monitor. Each type of monitor checks the status of a particular protocol, service, or application. For example, one type of monitor is HTTP. An HTTP type of monitor allows you to monitor the availability of the HTTP service on a pool, pool member, or node. A WMI type of monitor allows you to monitor the performance of a pool, pool member, or node that is running the Windows Management Instrumentation (WMI) software. An ICMP type of monitor simply determines whether the status of a node is up or down.
Monitor settings
Every monitor consists of settings with values. The settings and their values differ depending on the type of monitor. In some cases, the BIG-IP system assigns default values. For example, the following shows the settings and default values of an ICMP-type monitor.
   Name my_icmp
   Type ICMP
   Interval 5
   Timeout 16
   Transparent No
   Alias Address * All Addresses
Note: If you want to monitor the performance of a RealNetworks® RealServer server or a Windows®-based server equipped with Windows Management Instrumentation (WMI), you must first download a special plug-in file onto the BIG-IP system.

Task summary

To implement a health or performance monitor, you perform these tasks.

Task list

Creating a custom monitor

Before creating a custom monitor, you must decide on a monitor type.
You can create a custom monitor when the values defined in a pre-configured monitor do not meet your needs, or no pre-configured monitor exists for the type of monitor you are creating.
Important: When defining values for custom monitors, make sure you avoid using any values that are on the list of reserved keywords.
  1. On the Main tab, click Local Traffic > Monitors .
    The Monitor List screen opens.
  2. Click Create.
    The New Monitor screen opens.
  3. Type a name for the monitor in the Name field.
  4. From the Type list, select the type of monitor.
    The screen refreshes, and displays the configuration options for the monitor type.
  5. From the Import Monitor list, select an existing monitor.
    The new monitor inherits initial configuration values from the existing monitor.
  6. From the Configuration list, select Advanced.
    This selection makes it possible for you to modify additional default settings.
  7. Configure all settings shown.
  8. Click Finished.

Creating a load balancing pool

You can create a load balancing pool (a logical set of devices such as web servers that you group together to receive and process traffic) to efficiently distribute the load on your server resources.
Note: You must create the pool before you create the corresponding virtual server.
  1. On the Main tab, click Local Traffic > Pools .
    The Pool List screen opens.
  2. Click Create.
    The New Pool screen opens.
  3. In the Name field, type a unique name for the pool.
  4. For the Health Monitors setting, in the Available list, select a monitor type, and click << to move the monitor to the Active list.
    Tip: Hold the Shift or Ctrl key to select more than one monitor at a time.
  5. From the Load Balancing Method list, select how the system distributes traffic to members of this pool.
    The default is Round Robin.
  6. For the Priority Group Activation setting, specify how to handle priority groups:
    • Select Disabled to disable priority groups. This is the default option.
    • Select Less than, and in the Available Members field type the minimum number of members that must remain available in each priority group in order for traffic to remain confined to that group.
  7. Using the New Members setting, add each resource that you want to include in the pool:
    1. (Optional) In the Node Name field, type a name for the node portion of the pool member.
    2. In the Address field, type an IP address.
    3. In the Service Port field, type a port number, or select a service name from the list.
    4. (Optional) In the Priority field, type a priority number.
    5. Click Add.
  8. Click Finished.
The load balancing pool appears in the Pools list.

Creating a virtual server

A virtual server represents a destination IP address for application traffic.
  1. On the Main tab, click Local Traffic > Virtual Servers .
    The Virtual Server List screen opens.
  2. Click the Create button.
    The New Virtual Server screen opens.
  3. In the Name field, type a unique name for the virtual server.
  4. In the Destination Address/Mask field, type the IP address in CIDR format.
    The supported format is address/prefix, where the prefix length is in bits. For example, an IPv4 address/prefix is or, and an IPv6 address/prefix is ffe1::0020/64 or 2001:ed8:77b5:2:10:10:100:42/64. When you use an IPv4 address without specifying a prefix, the BIG-IP® system automatically uses a /32 prefix.
    Note: The IP address you type must be available and not in the loopback network.
  5. In the Service Port field, type a port number or select a service name from the Service Port list.
  6. In the Resources area of the screen, from the Default Pool list, select the relevant pool name.