Graphical User Interface › Application Configuration › Resources Tab

Resources Tab

The Resources tab allows you to control how much resources the application requires and will be allowed to take.

By default, CA AppLogic® for System z calculates the resource range of the application based on the resource ranges of all appliances used in the application.

Note: If you don't want to constrain the application further or simply don't know yet what constraints you want, leave the default settings (clear all constraints).

CA AppLogic® for System z provides two ways to constrain further the amount of resources to be allocated to the application:

• By number of servers
• By resource range

In addition, you can select a subset of servers in the system, on which the application can be scheduled. Such constraints allow you to specialize this particular instance of the application for production and sandbox (testing) environments.

CA AppLogic® for System z determines the actual amount of resources to be given to an application when you start the application. Whatever resources are available or specified when starting the application must fit within the range defined here.

Be aware of the following:

• You can fix the exact amount of resources to be used when starting the application by specifying the maximum values equal to the minimum. This will help ensure that (a) no freedom will be given to the CA AppLogic® for System z scheduler, (b) the application will not start unless at least that much resources are available, and (c) the application will take no more than that much resources.
• On this screen you can only reduce the resource range: specify a higher minimum or lower maximum for resources.

The Resources contains the following information and configurable fields:

• Limit the resource range - Constrain by Resources--Specify the resource range for each hardware resource separately (CPU, memory and bandwidth).

  The following resource types can be specified:

  • CPU--Portion of CPU or number of CPUs to be allocated for the application. Fractional amounts can be specified as a decimal number (for example, 0.5 or 3.5). Whole CPUs are specified simply as an integer (for example, 12).
  • Memory--Amount of memory to be allocated for the application. The amount can be specified as an integer value in Megabytes (for example, 512M) or in Gigabytes (for example, 9G).

Bandwidth--Amount of network bandwidth to be allocated for this application (total for all terminals/interfaces, including the internal communication inside the application). The amount can be specified as an integer value in Megabits/sec (for example, 10M) or in Gigabits/sec (for example, 1G).
Important: CA AppLogic® for System z now allows administrators to enable/disable the oversubscription of network bandwidth on a grid for the backbone/internal network (disabled by default). If enabled, appliances may use more bandwidth than their configured network bandwidth (as in CA AppLogic® for System z 2.1.1 and all previous releases). If disabled, CA AppLogic® for System z enforces the maximum network bandwidth for each appliance based on its configured network bandwidth (as in CA AppLogic® for System z 2.3+). Once the used bandwidth for the appliance closely approaches its configured bandwidth, CA AppLogic® for System z randomly drops network packets for that appliance. For as long as the used appliance bandwidth exceeds the configured bandwidth, CA AppLogic® for System z drops all network packets for that appliance.

The enabled/disabled state of the resource oversubscription for bandwidth is displayed on the grid's dashboard.

The enabling/disabling of this feature is controlled through CA AppLogic® for System z hotfix hf2668. Future CA AppLogic® for System z releases will allow the user to control resource oversubscription through the CA AppLogic® for System z command line interface and appliance configuration.

A range can be specified for each resource type. The range defines the normal operating parameters desired for the application in production environment.

• Minimum--The minimum amount of a resource that the application needs to work at all. This is useful to allow running the application in functional testing environments, where the application is not expected to run under production load, and therefore can run with much less resources. Contrast this with the Default below, which is amount of resources needed for production use.
• Maximum--The maximum amount of a resource that the application will be allowed to take. Typically this is the maximum that the application can use (for example, giving it more resources will not increase performance). The application will not be allocated more than the specified maximum amount, helping ensure that it will not be able to take resources away from other applications -- think of it as a quota.
• Default--The minimum amount of a resource that the application should be provided with for normal operation in production environments. The application will not be started unless at least that much can be allocated for it. Specifying a default helps ensure that the application will work within certain "guaranteed" resource amount -- think of it as a service level agreement (SLA) for that resource.

Note: You can easily see which values override the defaults -- they are displayed in bold. If you want to restore the default value for a given resource, use the restore button next to the value.

• Limit the set of servers - Constrain by Server Names

Be aware of the following:

• You can also select on which particular servers of the system you would like the application to run.
• The list of servers on your system can be found by executing the server list shell command.
• If CA AppLogic® for System z is not able to honor the specified serverset constraints due to one or more servers not having enough resources, CA AppLogic® for System z will start the application on other server(s) provided there are available resources and log a dashboard message.
• This is an advanced option that may be useful when you want to run several applications on the same system and the results produced by the CA AppLogic® for System z scheduler are not satisfactory. In most cases you should leave this constraint disabled.