Throttle Levels for the Surge Protection Feature of a NetScaler Appliance

Throttle Levels for the Surge Protection Feature of a NetScaler Appliance

book

Article ID: CTX115684

calendar_today

Updated On:

Description

You can use the Surge Protection feature of a NetScaler appliance to protect server resources from high network traffic load. The Surge Protection feature queues the client requests and releases the same to the server in a controlled manner. This prevents saturation of the server resources. This feature is helpful in the scenarios where you have limited server capacity and the network traffic is consistent.

Throttle Levels of the Surge Protection Feature

You can configure the Surge Protection feature for a service and set a base threshold value and a throttle rate. The threshold value ensures that the Surge Protection triggers as soon as the network traffic reaches the threshold value. With the throttle rate, you can control the rate at which you need to release the new connections to the back end server.

You can specify the following throttle setting for the Surge Protection feature:

  • Normal

  • Aggressive

  • Relaxed

    When you specify the required value for the throttle settings, the Surge Protection feature handles the appropriate connections opened to the back end server. The following table lists the throttle rate for each throttle setting for Surge Protection:

    Throttle Settings

    Throttle Rate (Connections, Milliseconds)

    Normal

    200,10

    400,20

    800,50

    2000,100

    Aggressive

    16,10

    200,30

    500,50

    1000,500

    Relaxed

    500,10

    1000,10

    2000,10

    3000,10

    As specified in the values for the throttle rate in the preceding table, the following scenarios explain how Surge Protection handles connection when you set throttle settings to Normal, which is the default setting:

    • The first 199 connections get unrestricted access to the back end server.

    • 200 to 399 connections are opened at the rate of 1 connection per 10 milliseconds.

    • 400 to 799 connections are opened at the rate of 1 connection per 20 milliseconds.

    • 800 to 1999 connections are opened at the rate of 1 connection per 50 milliseconds.

    • 2000 or more connections are opened at the rate of 1 connection per 100 milliseconds.

      Run the following command from the command line interface to view the surge protection parameters:
      show ns spParams

      Surge Protection parameters:
BaseThreshold: 200
Throttle: Normal

      Additional Resources

      Consider the following points when configuring the Surge Protection feature on a NetScaler appliance:

      • You can enable or disable this feature globally as well as at the service level. If enabled globally, it is inherited by all services created after the change.

      • The Threshold is a global value and applies to all configured services with Surge Protection enabled.

      • The default values work well for most circumstances. However, when equipped with high performance servers, you need to adjust this value to avoid creating a bottleneck at the NetScaler appliance.

      • You should not use the Surge Protection feature and the Use Source IP (USIP) mode at the same time for services of type HTTP.

      Issue/Introduction

      This article contains information about the throttle levels of the Surge Protection feature on a NetScaler appliance.
      Powered by Wolken Software