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SP_266134's avatar
SP_266134
Icon for Nimbostratus rankNimbostratus
Aug 03, 2018

http monitor

Hello guys, I ma trying to set up a monitor http for every 5 min interval. get some file with response code. GET /check HTTP/1.0\r\n\r\n interval 299 sec timeout 301 sec. return string : live Can any one tell me how long the monitor will detect the site is down. How many queiers are sent to the server ever in a 20 min windows. When the response is not live , when will the server node be marked down. I see the default values as 5 to 16 interval. Does it mean i need to multiple the interval*3 +1 which makes 5 min interval to be 16 min. So does this mean F5 determines to make the node after after 16 min. Are my calculations and understanding correct.

 

application delivery
BIG-IP
LTM

1 Reply

  • Chris_Grant's avatar
    Chris_Grant
    Icon for Employee rankEmployee
    Aug 03, 2018

    We recommend that you use a 3+1 interval timeout. Keep in mind, we keep sending monitors even when the system is down. A five minute interval is extremely long, but might make sense in your situation. Our default is a five second interval with a sixteen second timeout. In that situation (taking a simple SYN monitor), we would work as follows:

    0  sec - SYN
5  sec - SYN
10 sec - SYN
15 sec - SYN
16 sec - we would mark the pool member down here
20 sec - SYN
25 sec - SYN
30 sec - SYN
         SYN/ACK
         ACK - we would mark the pool member up here, unless told otherwise by the config.

    If you had an HTTP monitor, there would just be more traffic, and with a 5 minute interval and sixteen minute timeout, we would send a monitor every five minutes and mark the pool member down after sixteen minutes of no response. You would still have only four monitor outstanding, however.