Forum Discussion
kunjan_118660
Cumulonimbus
See if LB_FAILED event helps to log the failed request.
jaked_150553
Nov 11, 2014Nimbostratus
https://clouddocs.f5.com/api/irules/LB_FAILED.html
This article says that LB_FAILED cannot be used for perfromace layer4 type VIPs.