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The load evaluator is a thread in the IMA Service on a XenApp Server that calculates the load index for that server. The load index is an integer value from 0  to 10,000 that represents how busy is XenApp server. A value of zero represents no load, while a value of  10,000 indicates the particular server is fully loaded and is not accepting any new connections.

To dispaly the current load on the server, administrator can run the command qfarm /load or query farm /load. Load vaules as reported by qfarm utility:

0 to 9998   This is the normal range for Load Manager.
99999          No load evaluator is configured.
10000        Load is at 100 percent (full load).
20000       The AppCenter console contains an incorrect server edition or a license mismatch.
99990        Results when a custom administrator with restricted rights runs the following QFARM commands:
  • QFARM SERVER /APP
  • QFARM /APP
  • QFARM /APP <appname> The QFARM command may not return any results when a custom administrator runs the following queries: QFARM /DISC
  • QFARM /LOAD
  • QFARM /ZONELOAD

How the server load is calculated  ?

The current load is a result of the calculations and sum of the values of all the rules in each and every load evaluator which applies to the server. The base algorithm for establishing actual load is: Highest_Load + (Average_Other_Loads * .1)
One important factor to understand is once any single rule reaches its maximum value, the load value for that server becomes 10,000, effectively removing the individual server from contention for new sessions. Individual servers continuously update the respective zone data collector with their current score every 15 seconds under normal conditions, or after each and every logon or logoff of a user session.

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