Unusual high CPU cycles on iRule

Hi NiHo,

you should consider in your calculations how often each event is executed.

• RULE_INIT

  : Is only issued each time you load/save the config

• HTTP_REQUEST

  : Is issued on each request.

• LB_FAILED

  : Is issued on each request, but only if the POOL has been failed and if

  ( $status eq "1" )

  is not active.

In addition, if

( $status eq "1" )

or your POOL is down, then you will send a HTTP response on behalf of your servers and save the ressources required to handle server side connections. I would bet that an outtage/maintenance will even result in a lower CPU consumption compared to normal operation.

In the end just the

HTTP_REQUEST

event should be considered in your calculation. The iRule you've provided is already highly optimized. You may only save a few cycles by removing the

$status

variable and passing the results of

[class match -value "[virtual name]" equals "maintenance-list"]

directly into the

if { } then {

. But thats all about what you can do to further improve this iRule without over engineering it.

Also keep in mind, that you've to multiply the Cycles/Sec value of the spreatsheet with the total number of CPU cores in your system.

Cheers, Kai