Forum Discussion

Leon_Xu_378103's avatar
Leon_Xu_378103
Icon for Nimbostratus rankNimbostratus
Dec 21, 2018

ratio-least-connections-member doesn't work as expected

Hi All,

 

I set up a pool with ratio-least-connections-member LB mode and assign different ratios to pool members. But from a simple curl test it looks like LTM didn't distribute traffics based on it's LB mode, it behaved just like round-robin.

 

Did I misconfigure something?

 

I'm using F5 LTM VE, 13.1.1.2.

 

pool setting

 

 

test result

 

 

Thanks.

 

application delivery
BIG-IP
LTM
  • Dylan_375544's avatar
    Dylan_375544
    Icon for Cirrocumulus rankCirrocumulus
    Dec 21, 2018

    Well, I labbed out your situation and I have the same issue. It seems as if "least connections" takes precedence over "ratio".

     

    As soon as I changed my LB method to "Ratio (member)" the LB acted properly and heeded my ratios.

     

    As soon as I change it back to "Ratio Least Connections (Member)" it goes back to 50/50 between my two vips.

     

    My only advice would be to change your LB method to just "Ratio (member)"

     

    (my lab version was 13.1.1.3)

     

    -Dylan

     

    • Leon_Xu_378103's avatar
      Leon_Xu_378103
      Icon for Nimbostratus rankNimbostratus
      Dec 22, 2018

      Thanks Dylan!

       

      "Ratio (member)" works.

       

      For "Ratio Least Connection (Member)" mode, my understanding is "ratio" should take precedence over "least connections", but obviously it isn't. I'm wondering if this is a bug in V13. Not sure if other versions having this problem.

       

  • Raman_Kaushik's avatar
    Raman_Kaushik
    Ret. Employee
    Dec 22, 2018

    Try this:

     

    1. Keep 2 pool members active.
    2. Give ratio is 10 and 30. (basically 1:3)
    3. Reset the stats.
    4. curl -v -k [1-1000]<<<<<<<<<<<<
    5. The curl command will generate 1000 requests, however current connection would be just 4 on bigIP.
    6. Check the stats again.

    Worked for me.

     

  • Raman_Kaushik_3's avatar
    Raman_Kaushik_3
    Historic F5 Account
    Dec 22, 2018

    Try this:

     

    1. Keep 2 pool members active.
    2. Give ratio is 10 and 30. (basically 1:3)
    3. Reset the stats.
    4. curl -v -k [1-1000]<<<<<<<<<<<<
    5. The curl command will generate 1000 requests, however current connection would be just 4 on bigIP.
    6. Check the stats again.

    Worked for me.

     

  • Stanislas_Piro2's avatar
    Stanislas_Piro2
    Icon for Cumulonimbus rankCumulonimbus
    Dec 22, 2018

    I never played with ratio least connection member algorithm, but it seems it is like that:

     

    It evaluate number of connection * member ratio, then do the same as least connection

     

    If you do tests with only one curl, when the request is ended, connection closes, so number of connection for each member equals 0

     

    Least connection algorithm do round robin on all member matching same connection number