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wowchens's avatar
wowchens
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Feb 25, 2008

Pool Member Reselect doesn't work

Hello All:

 

 

The requirement for one of our applications is that web services up/down should be 100%(the business says 200%) transparent to the users. Front end is a thin client App which makes web service calls to 2(right now for the Proof of concept, but will be having more than 2) web servers that are behind LTM. There is a simple http monitor that polls for test.aspx with a Reponse string every 1 second and timeout is set to 4 seconds. In the pool configuration, I have "Reselect" selected for Action on Service down. As far as my understanding goes, Reselect means when a service is not available LTM selects a different node instead of forwarding to the one that is down.

 

 

My problem is that there is a lag of about 15 to 20 seconds before the requests are sent to the alternate node. Once I bring web service down on 1st node, it takes atleast 15 seconds or 3 to 4 re-tries on the client side to get it going. This behavior is seen even if we don't use "Reselect" option.

 

 

Am I doing something wrong? Please let me know your thoughts on this.

 

 

Thank You
management
monitoring

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  • Deb_Allen_18's avatar
    Deb_Allen_18
    Historic F5 Account
    Feb 25, 2008
    We've heard reports that the LB::reselect iRules command seems to have some induced latency as well.

     

     

    Please open a case with F5 Support so they can attempt to replicate the issue and send up a CR to get it fixed.

     

    (Check the FAQ @ the top of this forum for F5 Support contact info)

     

     

    /deb