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santosh_81454's avatar
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Apr 27, 2011

health monitor issues.




We are currently load balancing our app servers using the F5 boxes running v10.2.0.We tried using multiple health monitors but they failed / ineffective due to the following reasons. the app servers are running on ATG/Jboss. Please let me know if anyone faced this issue earlier and resolved it.




Http - Creating n number of sessions. The session created for the health monitor check do not terminate.


tcp - works fine under less traffic. But when performing load test or high traffic, the box flips the nodes active/inactive within seconds causing error in the site.


External Health monitor - We are using SNMP and this is causing the CPU to be very high. Currently we just enabled the health monitor for one brand and its running at 79% avg. cpu. (We have five more brands to go)


inband monitor - is not effective as it marks the node active even when the node is disabled.


3 Replies

  • Hi Santosh,



    Can you make a single (or less ideally, multiple) HTTP request(s) which either do not generate a session or generate a session and then expire it? If so, you could try to mimic that in an HTTP health monitor. If it requires multiple requests, you could build a script and external monitor which references the script.



  • Hi Aaron,



    Yes, we are also looking in that direction of creating just single http request. Is it possible in F5 to use a cookie or some header to, such that we re-use the same session for health monitoring instead of creating new sessions everytime ?








  • Hi Santosh,



    With an inbuilt monitor you cannot save something from one monitor response and reuse it for a later request. This type of functionality is only available via an external monitor which calls a shell script. Here is a template you could use for an external monitor:





    You'd need to modify this to save the output from one request and reuse it.