Step-by-Step Guide for SQL Server Always on Failover
Step-by-Step Guide for SQL Server Always on Failover Introduction SQL Server Always On Availability Groups provide high availability and disaster recovery capabilities for SQL Server databases. Synchronous commit mode ensures that data is committed to both the primary and secondary replicas, guaranteeing data integrity during failover. This guide provides detailed steps for performing both manual and automatic failovers in an Always On Availability Group. Part 1: Preliminary Checks and Preparations Before initiating any failover, whether manual or automatic, ensure the environment is healthy and ready for the transition. Step 1: Prerequisites Check – Synchronization State: Confirm that all secondary replicas are in the SYNCHRONIZED state. – Query to Check Synchronization State: SELECT ag.name AS [AvailabilityGroupName], ar.replica_server_name AS [ReplicaServerName], drs.synchronization_state_desc AS [SynchronizationState] FROM sys.dm_hadr_availability_replica_states AS drs JOIN sys.availability_replicas AS ar ON drs.replica_id = ar.replica_id JOIN sys.availability_groups AS ag ON ar.group_id = ag.group_id WHERE drs.synchronization_state_desc = ‘SYNCHRONIZED’; – Action: Ensure that all replicas are in the SYNCHRONIZED state to avoid any data loss during failover. – Verify Health of Availability Group: – Query to Check Availability Group Health: SELECT ag.name AS [AvailabilityGroupName], ags.primary_replica AS [PrimaryReplica], ags.operational_state_desc AS [OperationalState] FROM sys.dm_hadr_availability_group_states AS ags JOIN sys.availability_groups AS ag ON ags.group_id = ag.group_id; – Action: Ensure that the OperationalState indicates a healthy state for a successful failover. Step 2: Validate Readiness for Failover…
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