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hc_andy_35682
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Mar 17, 2010

Diff bt setting Max Conn Limit on Node and Pool Member?

Hi All,

 

 

I've read the doco below but still a little unclear as to when a virtual server might redirect the request to an available node and/or pool member and when it might sent back a tcp reset upon the max connection limit being reached.

 

 

SOL9849: The BIG-IP sends a TCP RST packet when a pool member or node connection limit is reached

 

https://support.f5.com/kb/en-us/solutions/public/9000/800/sol9849.html

 

 

1/ Connection limit set on node

 

 

We are using source address persistence in this case so the client will hit the same node. Just wondering what happens to the client when they hit the same node again but it's already reached it's max connection limit. Will the client receive a tcp reset or will the virtual server try another available node from the pool?

 

 

2/ Connection limit set on a pool member

 

 

What if this time the max conn limit was set on the pool member instead. Same thing as 1/ here with source address persistence being used. Once the pool member's max connection limit has been reached, will the client receive a tcp reset or will the virtual server try another available member from the pool?

 

 

Thanks.

 

 

Andy

4 Replies

  • Hi Andy,

     

     

    I'd suggest the best method for confirming the behavior you're asking about would be to set up a test VS with a couple of pool members, set very low connection limits and then test.

     

     

    Also note that you can override connection limits on the persistence profile.

     

     

    Aaron
  • Thanks Aaron,

     

     

    I'll do some testing and report back.

     

     

    Cheers.

     

     

    Andy
  • Hi Andy,

     

     

    If you find out more, could you post back here? You might also consider opening a support case to confirm what you find and ask them to update the connection limit behavior solution on AskF5.

     

     

    Thanks,

     

    Aaron
  • Hi Aaron,

     

     

    I will report back with my findings soon.

     

     

    Cheers.

     

     

    Andy