Forum Discussion

Dean_M_21414's avatar
Dean_M_21414
Icon for Nimbostratus rankNimbostratus
Jun 22, 2011

Different Pool, Same Members

Hi all,

 

 

We have the following

 

 

 

VS One

 

(with 600 second persistence)>

 

Pool A

 

> member 1, member 2

 

 

 

 

 

We also have:

 

 

 

Pool B

 

> member 1, member 2

 

 

 

 

 

 

 

 

 

 

 

 

 

We now need for VS One to be served by Pool B,. i.e. Pool B is identical to Pool A.

 

 

 

VS One is currently live with large load.

 

 

 

What are the implications for existing connections to VS One, if we simply change from Pool A to Pool B?

 

 

 

Will the f5 simply drop all active connections to Pool A, or will it taper them off, and migrate them to the new pool? If it migrates them, how does it do this without affecting the connection?

 

 

 

If the f5 doesn't natively handle this, could this be done seamlessly via an iRule?

 

 

 

The f5's are in an HA pair: what if I change the VS on the Standby device, then fail across (we have connection mirroring enabled)?

 

 

 

Regards

 

 

Dean

 

management
monitoring
  • Colin_Walker_12's avatar
    Colin_Walker_12
    Historic F5 Account
    Jun 22, 2011
    I guess I don't really understand the question here. You have two pools with the same members in them? What would the point of changing pools be if they are using the same back end servers? Or are you saying that there are two pools with individual members, and you want to migrate from the first set of nodes to the second?

     

     

    I'll have to test, but I"m pretty sure changing the resource of your VS won't automatically terminate all connections established to the members in Pool A. They should finish normally and all new connections should go through Pool B. I can test to confirm if that's what you're asking.

     

     

    Colin
  • Dean_M_21414's avatar
    Dean_M_21414
    Icon for Nimbostratus rankNimbostratus
    Jun 22, 2011
    Hi Colin,

     

     

    We actually have two VS's pointing to the same pool. A requirement has come about that we now separate these VS's such that each VS points to a separate pool, but both pools will have the same members. We want to manage the traffic of each VS at the pool level differently, but we cannot do so whilst both VS's point to the same pool.

     

     

    Hence the need to move one VS to a newly created pool, and hence the question regarding how the traffic will be affected during the move.

     

     

    Quote: "I'll have to test, but I"m pretty sure changing the resource of your VS won't automatically terminate all connections established to the members in Pool A. They should finish normally and all new connections should go through Pool B. I can test to confirm if that's what you're asking."

     

     

    That is exactly what I'm asking. Your testing this would be greatly appreciated.

     

     

     

    Regards

     

     

    Dean

     

  • Dean_M_21414's avatar
    Dean_M_21414
    Icon for Nimbostratus rankNimbostratus
    Jun 23, 2011
    Hi all,

     

     

    I've done some brief testing:

     

     

    1 x VS, with a persistence of 30s

     

    2 x pools, A and B

     

     

    when Pool A is the resource for the VS, it serves data. When the resource is changed to Pool B, if there is an active persistence record pointing to a member in Pool A, that active persistence record will have priority over a resource change to Pool B. Thus, it seems that persistence trumps resource allocation during a resource change. Which is what weas expected of the device.

     

     

    Regards

     

     

    Dean