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Dave_21103's avatar
Dave_21103
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Jun 26, 2014
Solved

LTM - Load Balancing iRule

We have a VIP that takes two connections per day coming from the same client. The client opens the two connections within the same second of each other, each connection stays open for 30 seconds. P...
application delivery
devops
iRules
LTM
  • nitass_89166's avatar
    nitass_89166
    Jun 29, 2014

    The intermittent issue is that sometimes the two connections get load balanced to one member and sometimes each member receives one connection. Is there an iRule I can put in place to ensure one connection goes to each member every time?

     

    what you are seeing is due to how cmp works. i think disabling cmp should work.

     

    sol14358: Overview of Clustered Multiprocessing (11.3.0 and later)

     

    http://support.f5.com/kb/en-us/solutions/public/14000/300/sol14358.html

     

    if you do not want to disable cmp, irule similar to Matt's suggestion is needed (global variable will demote cmp, so you have to store global_myvsconncnt in session table instead).

     

    sol13033: Constructing CMP-compatible iRules

     

    http://support.f5.com/kb/en-us/solutions/public/13000/000/sol13033.html

     

Matt_Breedlove_'s avatar
Matt_Breedlove_
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Jun 26, 2014

Hi Dave,

 

Sure, you will probably want to enable oneconnect on your VS. You said that the client opens two connections, but do you know for sure they are opening two completely seperate TCP sessions from the same client? More than likely, it is one TCP session, and two HTTP requests. If that is the case, and you are not using oneconnect profile on the VS, then the loadbalancer only chooses a backend server when setting up the TCP connection...meaning all those subsequent HTTP requests may or may not be on that same connection.

 

My first suggestion is to leave it at either Round Robin or Least Connection on the LB algo and just enable a oneconnect profile. See how that works for you.

 

If its not cutting the mustard, I can give you an irule that will force a per HTTP REQUEST division between two pool members, but you will still need/want oneconnect on the VS

 

Hope this helps Matt