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dragonflymr's avatar
dragonflymr
Icon for Cirrostratus rankCirrostratus
Mar 17, 2015

Member Disabled and persistence without Persistence Records

Hi,

 

According to docs when member is set to Disabled then it is accepting new connections for which Persistence Record pointing to disabled member exists.

 

What about types of persistence that are not using Persistence Records (GARP, cookie) is that still true? If so how LTM can figure out if there are any sessions that should be allowed to create new connections to disabled member?

 

Piotr

 

application delivery
deployment
LTM
TMOS
TMSH

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  • Max_Q_factor's avatar
    Max_Q_factor
    Icon for Cirrocumulus rankCirrocumulus
    Mar 17, 2015

    Piotr,

     

    When you disable a pool member that is part of a virtual server with a persistence profile of any type the virtual server still reviews the persistence information, whether the information is maintained on the F5 in a table, is on a client as a cookie, or is calculated on a per-IP or per-connection basis like a hash.

     

    Once the F5 validates the persistence using one or more of the persistence methods then it makes a decision on where to send the new connection.

     

    I am sorry that this answer sounds so general but it seems like a general question.

     

    • dragonflymr's avatar
      dragonflymr
      Icon for Cirrostratus rankCirrostratus
      Mar 17, 2015
      I should think twice before asking. Thanks for pointing me in the right direction. Piotr
    • Max_Q_factor's avatar
      Max_Q_factor
      Icon for Cirrocumulus rankCirrocumulus
      Mar 17, 2015
      It's cool. That is just my prospective and there are other people on devcentral that might have another prospective on this. General questions are not bad but sometimes it makes it difficult to give a specific response.
    • dragonflymr's avatar
      dragonflymr
      Icon for Cirrostratus rankCirrostratus
      Mar 17, 2015
      My question was probably two questions in one, and second was cleverly hidden :-) I figured out how LTM can always find out if new connection should be processed. What I am a bit not sure is what is the exact process for statefull and stateless persistence or rather when LTM can decide to not pass any connections to disabled node. 1. If there are Persistence Records present LTM should accept new connections until all records will expire, then should not accept any new connections - Am I right? 2. If stateless persistence is used (cookie or CARP) then LTM has to accept new connections as long as there is any active connection in connection table. When there is no active connection and LTM has no info about persistence (as this info is only contained in packet, like cookie) then there is no reason to keep member available for new connections. Or I am completely wrong and LTM will always pass new connection if based on info in packet given disabled member is target of connection? My assumption was that after some time there should be no connection to the disabled member and it could be safely turned off (so for example http service stopped for maintenance). Piotr