Forum Discussion
Randy_Johnson_1
Nimbostratus
NimbostratusMonitor settings - Interval, Timeout, etc.
Can someone provide an easy to understand description of the Monitor settings 'Interval' and 'timeout' ?
My understanding is that monitors default to a 5 second interval, with a 16 second timeo...
Hi Randy, I wondered that a while back and did some testing using nc and telnet while running tcpdump. My tests were run on early 10.x BIG-IP LTM using an HTTP monitor. Note sure which exact version. From my notes:
The interval takes effect whenever an HTTP health monitor connects to the pool member. This behavior is different if the health monitor passes or fails. For a passing monitor, the succesful GET will close the connection and mark the pool member up. The LTM will then use the interval timer to establish a new connection. For the default interval/timeout 5/16, the health monitor may invoke a new connection and GET around every 5 seconds.
For a failed monitor, the LTM will establish a connection to the pool member and send up to 4 GET's, per the interval set, before closing the connection. If, after 4 GET's, the timeout has not been met, the LTM will establish a new connection and will continue this behavior until the timeout has been exceeded. At that time the LTM will mark a pool member down.
sprashanthac_81So pretty much we cannot have an interval lesser than the original interval value. So looks like the rule is must as below always
Interval =< Timeout
Reason for the ask, the client is requesting for a interval of 5 but wants the switch over immediately when the application is down. Any response is appreciated what they are looking for is
Interval =< Timeout BUT when failure in response immediately switch over to another server
to have Interval >= Timeout which I am thinking is not logical but please suggest thank you