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  2. BIG-IP Local Traffic Management: Basics
  3. Dynamic Ratio Load Balancing
Manual Chapter : Dynamic Ratio Load Balancing

Applies To:

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BIG-IP AAM

  • 15.1.9, 15.1.8, 15.1.7, 15.1.6, 15.1.5, 15.1.4, 15.1.3, 15.1.2, 15.1.1, 15.1.0, 15.0.1, 15.0.0, 14.1.5, 14.1.4, 14.1.3, 14.1.2, 14.1.0

BIG-IP APM

  • 17.1.1, 17.1.0, 17.0.0, 16.1.5, 16.1.4, 16.1.3, 16.1.2, 16.1.1, 16.1.0, 16.0.1, 16.0.0, 15.1.9, 15.1.8, 15.1.7, 15.1.6, 15.1.5, 15.1.4, 15.1.3, 15.1.2, 15.1.1, 15.1.0, 15.0.1, 15.0.0, 14.1.5, 14.1.4, 14.1.3, 14.1.2, 14.1.0

BIG-IP Analytics

  • 17.1.1, 17.1.0, 17.0.0, 16.1.5, 16.1.4, 16.1.3, 16.1.2, 16.1.1, 16.1.0, 16.0.1, 16.0.0, 15.1.9, 15.1.8, 15.1.7, 15.1.6, 15.1.5, 15.1.4, 15.1.3, 15.1.2, 15.1.1, 15.1.0, 15.0.1, 15.0.0, 14.1.5, 14.1.4, 14.1.3, 14.1.2, 14.1.0

BIG-IP Link Controller

  • 17.1.1, 17.1.0, 17.0.0, 16.1.5, 16.1.4, 16.1.3, 16.1.2, 16.1.1, 16.1.0, 16.0.1, 16.0.0, 15.1.9, 15.1.8, 15.1.7, 15.1.6, 15.1.5, 15.1.4, 15.1.3, 15.1.2, 15.1.1, 15.1.0, 15.0.1, 15.0.0, 14.1.5, 14.1.4, 14.1.3, 14.1.2, 14.1.0

BIG-IP LTM

  • 17.1.1, 17.1.0, 17.0.0, 16.1.5, 16.1.4, 16.1.3, 16.1.2, 16.1.1, 16.1.0, 16.0.1, 16.0.0, 15.1.9, 15.1.8, 15.1.7, 15.1.6, 15.1.5, 15.1.4, 15.1.3, 15.1.2, 15.1.1, 15.1.0, 15.0.1, 15.0.0, 14.1.5, 14.1.4, 14.1.3, 14.1.2, 14.1.0

BIG-IP PEM

  • 17.1.1, 17.1.0, 17.0.0, 16.1.5, 16.1.4, 16.1.3, 16.1.2, 16.1.1, 16.1.0, 16.0.1, 16.0.0, 15.1.9, 15.1.8, 15.1.7, 15.1.6, 15.1.5, 15.1.4, 15.1.3, 15.1.2, 15.1.1, 15.1.0, 15.0.1, 15.0.0, 14.1.5, 14.1.4, 14.1.3, 14.1.2, 14.1.0

BIG-IP AFM

  • 17.1.1, 17.1.0, 17.0.0, 16.1.5, 16.1.4, 16.1.3, 16.1.2, 16.1.1, 16.1.0, 16.0.1, 16.0.0, 15.1.9, 15.1.8, 15.1.7, 15.1.6, 15.1.5, 15.1.4, 15.1.3, 15.1.2, 15.1.1, 15.1.0, 15.0.1, 15.0.0, 14.1.5, 14.1.4, 14.1.3, 14.1.2, 14.1.0

BIG-IP DNS

  • 17.1.1, 17.1.0, 17.0.0, 16.1.5, 16.1.4, 16.1.3, 16.1.2, 16.1.1, 16.1.0, 16.0.1, 16.0.0, 15.1.9, 15.1.8, 15.1.7, 15.1.6, 15.1.5, 15.1.4, 15.1.3, 15.1.2, 15.1.1, 15.1.0, 15.0.1, 15.0.0, 14.1.5, 14.1.4, 14.1.3, 14.1.2, 14.1.0

BIG-IP ASM

  • 17.1.1, 17.1.0, 17.0.0, 16.1.5, 16.1.4, 16.1.3, 16.1.2, 16.1.1, 16.1.0, 16.0.1, 16.0.0, 15.1.9, 15.1.8, 15.1.7, 15.1.6, 15.1.5, 15.1.4, 15.1.3, 15.1.2, 15.1.1, 15.1.0, 15.0.1, 15.0.0, 14.1.5, 14.1.4, 14.1.3, 14.1.2, 14.1.0
Manual Chapter

Dynamic Ratio Load Balancing

Introduction to dynamic ratio load balancing

You can configure Dynamic Ratio load balancing for pools that consist of RealNetworks® RealServer™ servers, Microsoft® Windows® servers equipped with Windows Management Instrumentation (WMI), or any server equipped with an SNMP agent such as the UC Davis SNMP agent or Windows 2000 Server SNMP agent.
To implement Dynamic Ratio load balancing for these types of servers, BIG-IP® Local Traffic Manager provides a special monitor plug-in file and a performance monitor for each type of server. The exception is a server equipped with an SNMP agent. In this case, the BIG-IP system provides the monitor only; no special plug-in file is required for a server running an SNMP agent.

Monitor plug-ins and corresponding monitor templates

For each server type, this table shows the required monitor plug-in and the corresponding performance monitor types.
Server Type
Monitor plug-in
Monitor Type
RealServer Windows server
F5RealMon.dll
Real Server
RealServer UNIX server
f5realmon.so
Real Server
Windows server with WMI
f5isapi.dll
 or
F5Isapi64.dll
 or
F5.IsHandler.dll
WMI
Windows 2000 Server server
SNMP agent
SNMP DCA and SNMP DCA Base
UNIX server
UC Davis SNMP agent
SNMP DCA and SNMP DCA Base

Overview of implementing a RealServer monitor

For RealSystem® Server systems, the BIG-IP® system provides a monitor plug-in that gathers the necessary metrics when you have installed the plug-in on the RealSystem Server system. Configuring a RealSystem Server for Dynamic Ratio load balancing consists of four tasks:
  • Installing the monitor plug-in on the RealSystem Server system
  • Configuring a Real Server monitor on the BIG-IP system
  • Associating the monitor with the server to gather the metrics
  • Creating or modifying the server pool to use Dynamic Ratio load balancing

Installing the monitor plug-in on a RealSystem server system (Windows version)

This task installs the monitor plug-in on a RealSystem Server system (Windows version).
  1. Download the monitor plug-in
    F5RealServerPlugin.dll
     from the BIG-IP system.
    The plug-in is located in the folder
    /usr/local/www/docs/agents
    .
  2. Copy
    F5RealServerPlugin.dll
     to the RealServer plug-ins directory. (For example,
    C:\Program Files\RealServer\plug-ins
    .)
  3. If the RealSystem Server process is running, restart it.
Once the plug-in is installed and compiled, you must configure a Real Server monitor, associate the configured monitor with the node (a RealSystem Server server), and set the load balancing method to Dynamic Ratio.

Installing and compiling a Linux or UNIX RealSystem server monitor plug-in

This task installs and compiles a Linux or UNIX RealSystem Server monitor plug-in.
  1. Using the
    .iso
     image, burn a CD-ROM of the BIG-IP system software.
  2. On the CD, navigate to the directory
    /downloads/rsplug-ins
    .
  3. Copy the file
    F5RealMon.src.tar.gz
     to the directory
    /var/tmp
     on the BIG-IP system.
  4. On the BIG-IP system, change to the directory
    /var/tmp
    :
    cd /var/tmp
  5. Use the UNIX
    tar
     command to uncompress the file
    F5RealMon.src.tar.gz
    :
    For example, you might enter
    tar -xvzf F5RealMon.src.tar
    .
  6. Change to the
    F5RealMon.src
     directory:
    cd F5RealMon.src
  7. Type the
    ls
     command to view the directory contents.
  8. To compile the source, use the instructions in the file
    build_unix_note
    .
  9. Start RealSystem Server.
Once the plug-in is installed and compiled, you must configure a Real Server monitor, associate the configured monitor with the node (a RealSystem Server server), and set the load balancing method to Dynamic Ratio.

Overview of implementing a WMI monitor

For Windows running Windows Management Instrumentation (WMI), the BIG-IP® system provides a Data Gathering Agent for the IIS server. Configuring a Windows platform for Dynamic Ratio load balancing consists of these tasks:
  • Installing the Data Gathering Agent on the IIS server
  • Configuring a WMI monitor on the BIG-IP system
  • Associating the monitor with the server to gather the metrics
  • Creating or modifying the server pool to use the Dynamic Ratio load balancing method
To enable a user to access WMI metrics on a Windows server, you must configure the WMI monitor on the BIG-IP system correctly.
The procedure for installing the Data Gathering Agent on an IIS server differs depending on whether the server is running IIS version 5.0, 6.0, or 7.0, and whether the Data Gathering Agent is the file
f5isapi.dll
 (or
f5isapi64.dll
), or the file
F5.IsHandler.dll
.
F5 Networks® recommends that you install only the Data Gathering Agent file that pertains to your specific configuration. Installing multiple Data Gathering Agent files could result in unwanted behavior.

IIS version support for the data gathering agent files

The procedure for installing the Data Gathering Agent on an Internet Information Services (IIS) server differs depending on which IIS version the server is running and whether the Data Gathering Agent is the file
f5isapi.dll
,
f5isapi64.dll
, or
F5.IsHandler.dll
. The following table shows each of the Data Gathering Agent files and the IIS versions that support each file.
The IIS versions listed in the following table are tested for compatibility by F5. The Data Gathering Agent
F5.IsHandler.dll
 can support newer versions of IIS that are not listed here.
Data Gathering Agent
IIS 5.0
IIS 6.0
IIS 7.0
IIS 7.5
IIS 8.0
IIS 8.5
f5isapi.dll
 (32-bit) and
f5isapi64.dll
 (64-bit)
Yes
Yes
N/A
N/A
N/A
N/A
F5.IsHandler.dll
 (32-bit, 64-bit, and .NET)
N/A
Yes
Yes
Yes
Yes
Yes

Installing the Data Gathering Agent F5.IsHandler.dll on an IIS 7.5 server

Do not install the files
f5isapi.dll
 or
f5isapi64.dll
 on IIS version 7.5. For IIS servers running version 7.5, always install the file
F5.IsHandler.dll
.
This task installs the Data Gathering Agent
F5.IsHandler.dll
 on an IIS 7.5 server.
  1. Create a
    scripts
     directory under the directory
    C:\Inetpub
     (
    C:\Inetpub\scripts
    ).
  2. Create a
    \bin
     directory under the
    scripts
     directory (
    C:\Inetpub\scripts\bin
    ).
  3. Copy the file
    F5.IsHandler.dll
     to the directory
    C:\Inetpub\scripts\bin
    .
  4. In the
    C:\Inetpub\scripts
     directory, create the file
    web.config
    .
    <?xml version="1.0" encoding="UTF-8"?>
                    <configuration>
                        <system.webServer>
                            <handlers>
                                <clear />
                                <add name="F5IsHandler" path="f5isapi.dll" verb="*" type="F5.IsHandler"
                                    modules="ManagedPipelineHandler" scriptProcessor="" resourceType="Unspecified"
                                    requireAccess="Script" preCondition="" />
                            </handlers>
                            <security>
                                <authentication>
                                    <anonymousAuthentication enabled="false" />
                                </authentication>
                            </security>
                        </system.webServer>
                        </configuration>
    In this example, the
    path
     value
    f5isapi.dll
     appears to be a mistake but is actually correct. It is the
    type
     value
    F5.IsHandler
     that directs the server to the correct file.
  5. Allow anonymous authentication to be overridden by using the
    appcmd
     command to set the override mode in the machine-level
    applicationHost.config
     file. 
    appcmd set config "Default Web Site/scripts"
/section:anonymousAuthentication
/overrideMode:Allow /commit:APPHOST
    appcmd
     is located in
    \windows\system32\intesrv
    .
  6. Set up a new application pool for the file
    F5.IsHandler.dll
    :
    1. From the
      Start
       menu, choose
      Control Panel
      .
    2. Choose
      Administrative Tools
      .
    3. Choose
      Internet Information Services (IIS) Manager
      .
    4. From
      Connections
      , expand
      MachineName
       (
      MachineName\UserName
      ).
    5. Right click the
      Application Pools
       menu and choose
      Add Application Pool
      .
    6. In the
      Name
       field, type
      F5 Application Pool
      .
    7. Click
      OK
      .
    8. From the
      Application Pools
       list, right click
      F5 Application Pool
       and choose
      Advanced Settings
      .
    9. Under the
      Process Model
       List, click
      Identity
      , and then click the button to the right of
      ApplicationPoolIdentity
      .
    10. From
      Built-in account
       select
      NetworkService
      .
    11. Click
      OK
      .
    12. Click
      OK
      .
  7. Create a new application named
    scripts
    :
    1. Expand
      Sites
      .
    2. Right click
      Default Web Site
       and choose
      Add Application
      .
    3. In the
      Alias
       field, type
      scripts
      .
    4. Change the application pool, click
      Select
      , select
      F5 Application Pool
       from the
      Application Pool
       list, and click
      OK
      .
    5. For the physical path, type the directory you created in step 1 (
      C:\Inetpub\scripts\
      ).
    6. Click
      OK
      .
  8. Change the
    Authentication
     setting to
    Basic Authentication
    :
    1. Select
      scripts
      .
    2. In the center pane, double click
      Authentication
      .
    3. Verify that the status of all items under
      Authentication
       is
      Disabled
      , except for the
      Basic Authentication
       item. To enable or disable an authentication item, right click the name and choose
      Enable
       or
      Disable
      .
Once you have installed the plug-in, you must configure a WMI monitor, associate the configured monitor with the pool member, and set the load balancing method to Dynamic Ratio.

Installing the Data Gathering Agent F5.IsHandler.dll on an IIS 8.0 or 8.5 server

Do not install the files
f5isapi.dll
 or
f5isapi64.dll
 on IIS version 8.0 or 8.5. For IIS servers running version 8.0 or 8.5, always install the file
F5.IsHandler.dll
.
This task installs the Data Gathering Agent
F5.IsHandler.dll
 on an IIS 8.0 or 8.5 server.
  1. Create a
    scripts
     directory under the directory
    C:\Inetpub
     (
    C:\Inetpub\scripts
    ).
  2. Create a
    \bin
     directory under the
    scripts
     directory (
    C:\Inetpub\scripts\bin
    ).
  3. Copy the file
    F5.IsHandler.dll
     to the directory
    C:\Inetpub\scripts\bin
    .
  4. Allow anonymous authentication to be overridden by using the
    appcmd
     command to set the override mode in the machine-level
    applicationHost.config
     file. 
    appcmd set config "Default Web Site/scripts" /section:anonymousAuthentication /overrideMode:Allow /commit:APPHOST
    appcmd
     is located in
    \windows\system32\inetsrv
    .
  5. Set up a new application pool for the file
    F5.IsHandler.dll
    :
    1. From the
      Start
       menu, choose
      Control Panel
      .
    2. Choose
      Administrative Tools
      .
    3. Choose
      Internet Information Services (IIS) Manager
      .
    4. From
      Connections
      , expand
      MachineName
       (
      MachineName\UserName
      ).
    5. Right click the
      Application Pools
       menu and choose
      Add Application Pool
      .
    6. In the
      Name
       field, type
      F5 Application Pool
      .
    7. Click
      OK
      .
    8. From the
      Application Pools
       list, right click
      F5 Application Pool
       and choose
      Advanced Settings
      .
    9. Under the
      Process Model
       List, click
      Identity
      , and then click the button to the right of
      ApplicationPoolIdentity
      .
    10. From
      Built-in account
       select
      NetworkService
      .
    11. Click
      OK
      .
    12. Click
      OK
      .
  6. Create a new application named
    scripts
    :
    1. Expand
      Sites
      .
    2. Right click
      Default Web Site
       and choose
      Add Application
      .
    3. In the
      Alias
       field, type
      scripts
      .
    4. Change the application pool, click
      Select
      , select
      F5 Application Pool
       from the
      Application Pool
       list, and click
      OK
      .
    5. For the physical path, type the directory you created in step 1 (
      C:\Inetpub\scripts\
      ).
    6. Click
      OK
      .
  7. Change the
    Authentication
     setting to
    Basic Authentication
    :
    1. Select
      scripts
      .
    2. In the center pane, double click
      Authentication
      .
    3. Verify that the status of all items under
      Authentication
       is
      Disabled
      , except for the
      Basic Authentication
       item. To enable or disable an authentication item, right click the name and choose
      Enable
       or
      Disable
      .
  8. Add a handler mapping:
    1. Select
      scripts
      .
    2. Click
      Handler Mappings
      .
    3. In the Actions pane on the right side of the screen, click
      Add Managed Handler
      .
    4. In the
      Request Path
       field, type
      F5Isapi.dll
      .
      The
      Request Path
       value
      f5isapi.dll
       appears to be a mistake but is actually correct. It is the
      Type
       value
      F5.IsHandler
       that directs the server to the correct file.
    5. From the
      Type
       list, select
      F5.IsHandler
      .
    6. Type a name, such as
      F5 IsHandler
      .
    7. Click the
      Requested Restrictions
       button.
    8. Clear the check box labeled
      Invoke handler only if request is mapped to:
    9. Click
      OK
      .
    10. Click
      OK
       again.
Once you have installed the plug-in, you'll need to configure a WMI monitor, associate the configured monitor with the pool member, and set the load balancing method to Dynamic Ratio.
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