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Frank_30524's avatar
Frank_30524
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Jun 03, 2008

Load Balance Question

I'm am new to bigip and herited a couple and have a question.

 

I have a pool with four nodes, round robin with priority group activation set at less than one. Ratio is all set at one and the priority group I have a node at 2 and other three nodes at 1. My problem is that sometimes the node with 2 priority gets overloaded and traffic is bounced to the other nodes, but it seems that all the traffic goes to one node with priority 1. Everytime this happens it does the same thing except it may be another node. I thought that it was susposed to round robin on the other three nodes? I don't know why it is not doing this. Any thoughts answers, questions or corrections, please let me know.

 

 

Thanks

 

Frank
dev
devops
iControl

13 Replies

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  • Frank_30524's avatar
    Frank_30524
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    Jun 03, 2008
    Yes, it looks like Persistence type is Source address affinity and Parent Profile is source_address. Also, Match Across Services is enabled.
  • Frank_30524's avatar
    Frank_30524
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    Jun 03, 2008
    It looks like that may be it. My question then is if that node has 25 connections, why would every connection that comes in persist to that one node instead of any other?
  • The_Bhattman's avatar
    The_Bhattman
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    Jun 03, 2008
    Based on what you had stated. You turned persistance on for source address affinity. Which means persistance is based on the client Ip address with a certain timeout value.

     

     

    Here is how it works. First time clients connect to the application, F5 checks to see if it's part of the persistance table. When it finds out it isn't it applies the load balancing method, in your case round robin. The next time the client returns (within the persistance timeout) it will return the client to the same node, regardless of the load balancing method. Therefore, Round Robin ONLY works the first time when the client is not part of the persistance table.

     

     

     

     

     

  • Frank_30524's avatar
    Frank_30524
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    Jun 03, 2008
    ok I understand the persistence, but all of the connections are going to the first node of the three. The other two are not getting any of the connections. That is the part I don't understand.
  • The_Bhattman's avatar
    The_Bhattman
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    Jun 03, 2008
    Are connections from the same client? Also in your persistance profile, do you have MASK turned on?

     

     

     

     

  • Frank_30524's avatar
    Frank_30524
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    Jun 03, 2008
    Some connections could be from the same client but not all of them. Mask is not turned on.
  • The_Bhattman's avatar
    The_Bhattman
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    Jun 03, 2008
    I would say that if you turned off persistance and have setup priority 2 with priority group activation set at less than one, then it shoudl round robin. Unless the connection never disconnected. The only truly way to know is to completely close all connections and allow the client's back in w/o persistance