This article describes the method to calculate the Load Evaluator Index on Desktop Delivery Controller (DDC).

Instructions

On Director Machine Details page, you can monitor the load evaluator index (Percentage) for different VDA machines.



To check the Load Evaluator Index Trends go to Trends>>Load Evaluator Index



You can also run the below powershell cmdlet on the  DDC to find the Load Evaluator Index of a specific VDA.

Get-Brokermachine machinename

The overall effective load index for a VDA is the maximum value of the largest index that is enabled plus 5% of the average of the remaining enabled indexes. The value is recalculated every 5 minutes when new data is received from the VDA, and is also adjusted when new sessions are established or sessions terminated. The value might also be recalculated if the load on the VDA changes significantly between the regular 5 minute updates.

Load Evaluator Index = Largest index + {(sum of remaining indexes) / (total number of indexes -1)} * 0.05

Example:
Load Evaluator Index = CPU + {(Memory + Disk +Session Count) / 3} * 0.05
*4 indexes are enabled.
*CPU value is greater than the others.

For example:

Note: The example calculation provided uses all load indexes

PS C:\Windows\system32> Get-BrokerMachine XD\XenApp4

:
LoadIndex                   : 9848
LoadIndexes                 : {CPU:7267, Memory:661, Disk:9633, $SessionCount$:5000}
:

Load Evaluator Index Total = Disk + {(CPU + Memory + Session Count) / 3} * 0.05
                                                  = 9633 + { (7267 + 661 + 5000) / 3 } * 0.05
                                                  = 9633 + {12928 / 3} * 0.05
                                                  =  9633 + { 4309.33 } * 0.05 
                                                  = 9633 + 215.4
                                                  = 9848.466
 

https://www.citrix.com/blogs/2014/09/22/citrix-director-trends-explained/