Environment

-> Disaster Recovery scenario is as below,

• PRIMARY DATA CENTRE goes down.
• The databases on Server JBSERVER2 should be made online and have the application connect to Database Server JBSERVER2.
• Failback Availability group back to JBSERVER1 when PRIMARY DATA CENTRE comes online.
• The changes made by the Application on JBSERVER2\IN2014 should be discarded.

-> Checking the current AlwaysON setup in SQL Server Management Studio,

-> The Database JB_DB contains a table named Table5, which we will use for testing.

USE [JB_DB]
GO
CREATE TABLE [dbo].[Table5](
[sno] [int] IDENTITY(1,1) NOT NULL,
[sname] [char](2000) NULL,
[sname1] [char](2000) NULL,
[sname2] [char](2000) NULL,
PRIMARY KEY CLUSTERED
(
[sno] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
) ON [PRIMARY]
GO

Set nocount on
insert into Table5 values ('a','b','c')
go 10002

-> Checking the row count for object Table5,

-> The PRIMARY DATA CENTRE goes down. 2 votes are lost as Database Server JBSERVER1 and file share witness is down. Now that 2 votes out of 3 votes are lost, the cluster goes down.

-> Checking the SQL Server instance and Eventlogs on JBSERVER2 when the Primary Data Centre is down.

-> Implementing Force Quorum on JBSERVER2.

-> Checking the SQL Server Instance after Force Quorum,

-> I will suspend the data movement now,

-> Right-click the availability group to be failed over, and select Failover.

-> Checking the SQL Server Instance after the failover with data loss.

-> The application can now connect to SQL Server Instance JBSERVER2\IN2014 using the Listener and use it. Let us insert a single row to the table for testing and make sure if it can be seen later after the failback.

insert into Table5 values ('a','b','c')
go

-> The PRIMARY DATA CENTRE comes online. Database Server JBSERVER1 and File witness are online now.

-> Connecting to JBSERVER1\IN2014 and Suspending the data movement,

-> We will failback the Alwayson Availability group to JBSERVER1\IN2014,

-> On SQL Server Instance JBSERVER1\IN2014, we will resume the data movement.

-> On SQL Server Instance JBSERVER2\IN2014, we will resume the data movement.

-> Checking the SQL Server Instance now,

-> Checking the row count for object Table5 on JBSERVER1\IN2014 after failback,

Thank You,
Vivek Janakiraman

Disclaimer:
The views expressed on this blog are mine alone and do not reflect the views of my company or anyone else. All postings on this blog are provided “AS IS” with no warranties, and confers no rights.