SNMP-DCA Monitor?

Did you get a chance to check out the 9.4 manual?

 

https://support.f5.com/kb/en-us/products/big-ip_ltm/manuals/product/LTM_config_guide_943.pdf.pdf

 

 

Page 12-38

 

With an SNMP DCA type of monitor, you can check the performance of a

 

server running an SNMP agent such as UC Davis, for the purpose of load

 

balancing traffic to that server. With this monitor you can define ratio

 

weights for CPU, memory, and disk use.

 

Performance monitors are generally used with dynamic ratio load balancing.

 

 

Page 12-39

 

When configuring an SNMP DCA custom monitor, you can use the default

 

CPU, memory, and disk coefficient and threshold values specified in the

 

monitors, or you can change the default values. Optionally, you can specify

 

coefficient and threshold values for gathering other types of data. Note that

 

if the monitor you are configuring is for a type of SNMP agent other than

 

UC Davis, you must specify the agent type, such as Win2000.

 

To understand how to use the coefficient and threshold values, it is

 

necessary to understand how the overall ratio weight is calculated. The

 

overall ratio weight is the sum of relative weights calculated for each metric.

 

The relative weights, in turn, are based on three factors:

 

• The value for the metric returned by the monitor

 

• The coefficient value

 

• The threshold value

 

Given these values, the relative weight is calculated as follows:

 

w=((threshold-value)/threshold)*coefficient

 

You can see that the higher the coefficient, the greater the relative weight

 

calculated for the metric. Similarly, the higher the threshold, the greater the

 

relative weight calculated for any metric value that is less than the threshold.

 

(When the value reaches the threshold, the weight goes to zero.)