Product Documentation

May 14, 2015

The adaptive threshold functionality in NetScaler Insight Center dynamically sets the threshold value for the maximum number of hits on each URL. If the maximum number of hits on a URL is greater than the threshold value set for the URL, a syslog message is sent to an external syslog server. The threshold value can be set for an interval of one day or one week.

Threshold-value calculation uses the following formula: Threshold value = Max hit * Threshold multiplier where
• Max hit is the maximum number of hits on a URL.
• Threshold multiplier is a user-defined integer value (default: 2).
Note: The adaptive threshold functionality is supported only on NetScaler 10.1.e.

Example

In the following example, duration of the threshold is set to Day.

On day 1, a syslog message is not sent because a threshold value is not calculated by NetScaler Insight Center for the previous day.

On day 2, if the maximum number of hits on a URL is 60 and the threshold value set by NetScaler Insight Center is 30 (Max Hit on day 1 * Threshold multiplier), the threshold value of day 2 is less than the maximum number of hits on day 2. Therefore, a syslog message is sent to an external syslog server.

On day 3, if the maximum number of hits on a URL is 10 and the threshold value is 120 (maximum hit on day 2 * Threshold multiplier), the threshold value of day 3 is greater than the maximum number of hits on day 3. Therefore, a syslog message is not sent to an external syslog server.

The following table shows an example of how a threshold value is calculated:

Day URL Max Hit Threshold Multiplier Threshold value = Max Hit * Threshold multiplier Syslog sent
Day 1 URL1 15 2 No threshold value is configured for Day1 No
Day 2 URL1 60 2 15*2 = 30 Yes Day 2 Max Hit (60) > Day 2 threshold value (30)
Day 3 URL1 10 2 60*2 = 120 No Day3 Max hit (10) < Day 3 threshold value (120)
Note: To configure a syslog server, see Configuring Syslog Server.
Setting the threshold value in NetScaler Insight Center
1. On the Configuration tab, navigate to NetScaler Insight Center>Thresholds.