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dacrud_18985's avatar
dacrud_18985
Icon for Nimbostratus rankNimbostratus
Oct 13, 2010

Least connections balancing method understanding

Hi,

 

 

I have a pool of 10 nodes configured in a least connections load balancing method. This pool is using a custom monitor (doing a GET and checking for text back) that we later found out it wasn't functioning correctly. Some nodes would be down (the port would still be up) and the custom monitor would still show it as ACTIVE,UP even though it wasn't serving anything properly. We then had a spike and one node end up receiving 60% of the traffic. When I checked the logs none of the nodes went down, all of them stayed up.

 

 

 

So my question is: On least connections method does the F5 still detect if a node in the pool is actually serving traffic? This is my only guess for this.. because all nodes were up but yet only maybe one or a few were still serving up traffic and only one received 60% of the connections.

 

 

 

Any help would be much appreciated. Thanks.

 

management
monitoring
  • nathe's avatar
    nathe
    Icon for Cirrocumulus rankCirrocumulus
    Oct 14, 2010
    Hi Dacrud

     

     

    Least Connections is only concerned with the current connection count between the big-ip and the server, not whether the server is serving traffic. If the pool member is up and it's his turn for a connection (i.e. currently has the least number of connections) it gets one.

     

     

    One reason why a pool member would receive most of the connections is if it went offline for a period, once it was back online it would have potentially far fewer current connections, in comparison to the other pool members. This member would then receive the necessary amount of subsequent connections before parity with the others was achieved.

     

     

    Least connections doesn't take into account what other traffic the pool member is serving, rather only connections from the VS specifically.

     

     

    Hope the above is all correct and useful info?

     

     

    N