Data360 DQ+

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  • 1.  Application DB

    Posted 03-24-2021 09:17

    How often Application DB and Standby Application DB  are replication , And in case of Application DB down how long it takes for the Standby Application DB to take over ?



  • 2.  RE: Application DB

    Employee
    Posted 03-24-2021 14:10

    Hi Gopi,

    It looks like the standby application DB is a "warm standby".  In case the Application DB goes down, it does not automatically failover to the standby DB and you will have to follow the instructions in our Install guide "Switching from your standby server back to your primary server" found on page 65.  Application db can also be manually backed up via the following script residing in the the install bin directory that could potentially be configured in a cronjob to recurring backups too.  

    backupApplicationDb
    If you want to backup and restore Application DB, you can follow the instructions in the guide "Restoring the system" found on page 56.

     



  • 3.  RE: Application DB

    Employee
    Posted 03-24-2021 14:12

    Attached the install guide for your reference.  

     

    Attached files

    Data360_DQ+_Enterprise_Installation_Guide.pdf

     



  • 4.  RE: Application DB

    Employee
    Posted 03-31-2021 05:27

    Hi Gopi,

    Just wanted to add more details to your question regarding the applicationdb (postgres), the postgres replication between primary and standby uses repmgr. The replication should be near real time. It is done asynchronous to the the transaction committing on the primary but should happen soon after the commit. So, the standby should be close to the state of the primary at all time unless there is a hiccup in the network connection between primary and standby or the standby goes down. When the primary goes down, the standby will automatically take over. When the primary is ready to come back up, the process requires some manual intervention. The steps to bring back the primary are documented in "Switching from your standby server back to your primary server" in the enterprise install guide as attached in the install guide above.  A few additional things to mention before bringing back the primary:

    • The first step should be to shut down the application servers.

    • At no time should the primary be brought back up while the application servers are up. This could lead to a split brain situation.

    • At no time should the primary be brought back up before a backup of the standby is taken which in turn should not happen till the application servers are shut down.