Loss of Primary Data Centre.How to manually failover in SQL 2012 three nodes with AG on

Ken 21 Reputation points
2021-10-04T05:08:51.253+00:00

Hi Everyone,

We are planning for DR where we have two DataCentre's one in location 'A' and other one in location 'B'. Currently our Primary DC is in location 'A' and we are planning to bring down Data center location 'A' . In case of Disaster Recovery where DC 'A' goes down , we need to bring up our secondary DC which is in location 'B'. The current setup of three node cluster failover with Always On configiured.

SQL version on three node cluster is SQL 2012 SP4 enterprise edition

we have three node clusters :

SQL01P (Primary) -Automatic failover -> Synchronus Commit
SQL02P(secondary) - Automatic failover -> Synchronus commit
SQL03P (secondary) - Manual failover -> Asynchronus commit

SQL01P & SQL02P is in synchronus commit whereas SQL03P is in Asynchronus commit. Both SQL01P & SQL02P servers belong to same Data Center 'A' whereas SQL03P is in secondary Data centre location 'B'.

My question is when our primary DC 'A' goes down how we gonna bring up secondary DC 'B' ?
what are the steps required to bring up secondary DC 'B'?

Please help.

Regards,
Ken

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  1. Olaf Helper 40,156 Reputation points
    2021-10-04T07:03:04.943+00:00

    My question is when our primary DC 'A' goes down how we gonna bring up secondary DC 'B' ?

    If you setup everything correctly, then the secondary in a failover cluster comes up automatically; that's what a cluster is good for.


  2. AmeliaGu-MSFT 13,961 Reputation points Microsoft Vendor
    2021-10-05T07:42:23.187+00:00

    Hi Ken-9235,

    Where is the Quorum? If you have two nodes and disk witness (or file share witness) in primary data center A, and the whole site
    goes down, you will need to force the start of the cluster on the remaining node in your DR site because you have lost too much at one time.
    You can change the availability mode of the secondary replica SQL06P on the site B from asynchronous to synchronous with manual failover or automatic failover, do a failover from the primary data center to remote data center before shutting down the primary data center.

    Best Regards,
    Amelia