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Dean_M_21414's avatar
Dean_M_21414
Icon for Nimbostratus rankNimbostratus
Nov 15, 2010

Monitoring wrong?

Hi all,

 

 

Just configured a pool with 2 x Server 2008 members (using port 443). The LTM is managing only 443 (https) traffic from the VS to the Pool ; no ssl offload, no NAT, no SNAT, no http profiles, no priority groups. Just using the device as a 'vanilla' LTM. The load bal method is Least Conn (member), yet the statistics for the pool shows that one member is getting a lot more traffic (approx 35x) than the other. The only addition is a source address persistence of 600s.

 

 

As an F5 noob, where do I start looking? Is the monitoring wrong? Where can I check?

 

 

Regards

 

 

Dean

 

management
monitoring

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  • hooleylist's avatar
    hooleylist
    Icon for Cirrostratus rankCirrostratus
    Nov 15, 2010
    Hi Dean,

     

     

    Here's a SOL to start with:

     

     

    SOL10430: Causes of uneven traffic distribution across BIG-IP pool members

     

    http://support.f5.com/kb/en-us/solutions/public/10000/400/sol10430.html

     

     

    Aaron
  • Dean_M_21414's avatar
    Dean_M_21414
    Icon for Nimbostratus rankNimbostratus
    Nov 16, 2010
    Hello all,

     

     

    After gathering stats for abt 20 hours, I suspect that the issue is one of the number of connections. In 20 hours, we've had a total of about 380 connections , split in a 5:1 ratio. Comparing this to our busier Pool, which has has 20 thousand connections over the same period, yields an explanation: a single connection in the quiet pool is completed 5 times out of 6 BEFORE a new connection is initiated. Thus, for 5 out of 6 connections, the 'first' server is given the request because there are no other connections. This is probably borne out by the fact that the busier pool is far more evenly dstributing the load between the two members.

     

     

    Dean

     

     

    PS, Aaron, tks for the support doc.
  • Dean_M_21414's avatar
    Dean_M_21414
    Icon for Nimbostratus rankNimbostratus
    Nov 16, 2010
    ...and we're running 9.4.5, so this probably applies:

     

     

    http://support.f5.com/kb/en-us/solutions/public/7000/900/sol7979.html

     

    Regards

     

     

    Dean
  • hooleylist's avatar
    hooleylist
    Icon for Cirrostratus rankCirrostratus
    Nov 16, 2010
    Nice troubleshooting. Thanks for posting what you found. Upgrading to 10.2 should resolve the CR you found and provide a lot more fixes.

     

     

    Aaron