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5 Replies Latest reply: Apr 24, 2012 1:39 AM by 893050 RSS

TimesTen 11.2 and Clusterware (masterVIP : why need a pair of VIPs?)

Nicosa Expert
Currently Being Moderated
Hi guys,

I'm on a project a migrating from TimesTen 7.0.5.16 to TimesTen 11.2.1.7.
We have severals datastore invloving both Active-standby Pair and AsynchronousWriteThrought Cache Groups.
More over, those active-standby pairs are "clustered" by Oracle Clusterware.
+(I use clustered between quotes as TimesTen 7.0 isn't clusterware aware, and so the clustering is done using home made scripts.)+

From the CRS point of view, the active-standby pair is seen as a ressource which is dependant of a VIP ressource. Hence when asking the CRS to start the datastore ressource, it first starts the VIP on the machine where the active store will be.

When looking at the 11.2 way of clustering, I see a parameter of the cluster.oracle.ini named MasterVIP which expects to have a pair of VIPs.

My question is : Why do I have to give a pair ?
I would expect to only give 1 VIP for an active-standby pair.
This VIP would be used by client application to connect to the active datastore, and would relocate to the other machine in case of a switchover/failover.
I must be missing something... can someone shed some light on that ?
  • 1. Re: TimesTen 11.2 and Clusterware (masterVIP : why need a pair of VIPs?)
    ChrisJenkins Guru
    Currently Being Moderated
    MasterVIP takes two (V)IP addresses. As I understand it, the first VIP is assigned to the 'active' master and the second VIP is assigned to the 'standby' master. When there is a failover the VIPs move accordingly. This allows applications to explictly connecto to the 'active' or the 'standby'. Some apps may want to always connect to the standby (e.g. reporting apps).

    Chris
  • 2. Re: TimesTen 11.2 and Clusterware (masterVIP : why need a pair of VIPs?)
    Nicosa Expert
    Currently Being Moderated
    Hi Chris,

    Thanks for the information. It makes sense. The documentation wasn't clear on how thoses 2 VIPs were used.
    I'll give it a test tomorrow if I have time and post the results here, so it might help others.
  • 3. Re: TimesTen 11.2 and Clusterware (masterVIP : why need a pair of VIPs?)
    Nicosa Expert
    Currently Being Moderated
    Hi,

    Up on the topic.
    Sorry for the delay, the platform to test on was not available to me...

    I've done some tests using TimesTen with CRS, and I'm a bit disappointed : The VIPs supplied in the MasterVIP parameters do not seem to be switched when the roles of active-standby pair is switched !
    If I use the first VIP given in MasterVIP, I always get on my "first" node datastore which can be either Master or Standby...
    (o_O)

    That leaves me with 2 questions :
    - what VIP should the applications use in order to always connect to the master ???
    - what is the point I'm missing with VIP that do not "switch" between datastores of the active standby pair ???

    Hope someone can shed some light on this.
  • 4. Re: TimesTen 11.2 and Clusterware (masterVIP : why need a pair of VIPs?)
    Nicosa Expert
    Currently Being Moderated
    Self replying :

    Ok, I think I got it.
    In the case of an active-standby pair using clusterware, the client application should have TTC_server and TTC_server2 configured in the datastore declaration.

    Something like :
    [masterDS]
    TTC_server=argument#1_of_masterVIP_parameter
    TTC_server2=argument#2_of_masterVIP_parameter
    TTC_SERVER_DSN=myDSN
    
    [standbyDS]
    TTC_server=argument#2_of_masterVIP_parameter
    TTC_server2=argument#1_of_masterVIP_parameter
    TTC_SERVER_DSN=myDSN
    Using upper masterDS definition, the client always get to the active datastore.
    Using the lower standbyDS, the client always get to the standby datastore.
  • 5. Re: TimesTen 11.2 and Clusterware (masterVIP : why need a pair of VIPs?)
    893050 Newbie
    Currently Being Moderated
    Hi Nicosa,

    Just like Chris said:Some apps may want to always connect to the standby.
    But no matter what I configured as above [masterDS] or [standbyDS],the client always get to the active datastore.
    Do you config that way and it work? Thanks
    ps: my tt version=11.2.2.2.0

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