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lipos_54863's avatar
lipos_54863
Icon for Nimbostratus rankNimbostratus
Aug 21, 2009

fallback persistence

Do you guys know the algorithm behind the Fallback persistence?

 

I'm using cookie insert method for one of our customers and everything is working fine. I set up a fallback persistence to source IP just in case... (one client was complaining once before, but we weren't able to reproduce the persistence problem).

 

 

I decided to test it.

 

I'm logging in to the website and blocking the cookie using Firefox's "Extended Cookie Manager". Persistence fails right after.

 

It seems that Fallback persistence is not kicking in :/

 

 

Idea explanation for it?

 

config
design

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  • hooleylist's avatar
    hooleylist
    Icon for Cirrostratus rankCirrostratus
    Aug 24, 2009
    If you check the persistence records using the GUI under Statistics | Persistence or the CLI using 'b persist all show all', do you see a source address persistence record? You might try using an iRule to log the source address persistence using persist lookup (Click here) and the LB_SELECTED and LB_FAILED events.

     

     

    Aaron
  • lipos_54863's avatar
    lipos_54863
    Icon for Nimbostratus rankNimbostratus
    Aug 24, 2009
    I will definitely try it, but I get the impression that fall-back source IP persistence should kick in if cookie is blocked?

     

     

    Thx
  • hooleylist's avatar
    hooleylist
    Icon for Cirrostratus rankCirrostratus
    Aug 24, 2009
    Hi lipos,

     

     

    You're correct that the fallback persistence method should be used if the client doesn't present a valid persistence cookie.

     

     

    Which LTM version are you running? Are you on a platform and version which supports CMP? If so, is CMP enabled on the virtual server? You can check SOL7751 (Click here) for details on CMP and its incompatibility with many features.

     

     

    Aaron
  • lipos_54863's avatar
    lipos_54863
    Icon for Nimbostratus rankNimbostratus
    Sep 01, 2009
    CMP is enabled on the VS.

     

    Any idea?

     

     

    - A rate class - not running any

     

    - iRules global variables - no using it

     

    - A persistence profile or iRule using a method other than cookie persistence - using insert cookie persistence as primary peristance

     

    - Traffic Management Operating System (TMOS) plug-ins - nope

     

    - An SSL profile is referenced, but SSL CMP is not licensed for the system - nope
  • hooleylist's avatar
    hooleylist
    Icon for Cirrostratus rankCirrostratus
    Sep 01, 2009
    If you're trying to use fallback source address persistence that is a persistence method other than cookie insert persistence and therefore LTM would need to store the persistence info in memory. As far as I'm aware that memory is specific to the TMM the request is handled by. So if you're seeing CMP actually used on the VIP, then it might explain the failure. If you explicitly disable CMP on the VIP and retest, do you still see the persistence failure?

     

     

    Aaron