What is Geo Replication in Azure ?
Geo replication in Azure specifically Active Geo Replication is a feature that allows you to create a continously synchronized readable secondary database for your primary database.This secondary db can be in same region or in different region.
Its primary purpose is to provide Business continuity and enable quick disaster recovery for individual databases in case of a regional disaster or large scale outage . It works by asynchronously replicating transaction logs from primary to all seondary db's.
Upto 4 secondary replicas can be created.
To add the replicas - Azure portal-Primary database-Data management-Replica- Create replica- select seondary server name , By default configuration,dbname will be auto populated .
Also this can be done by Tsql, Powershell-single db,Powershell-Elastic pool,REST API-Single db.
By Tsql
On Master db on primary server
ALTER DATABASE [YourDatabaseName] ADD SECONDARY ON SERVER [SecondaryServerName] WITH (ALLOW_CONNECTIONS = ON)
To failover
AZURE PORTAL-Replicas-click 3 dots and do forced failover , the server on which failover is initiated becomes primary and original primary will be secondary.
Stop replication
Azure Portal-Replicas-click 3 dots and stop replication, this will remove the server from replicas but the server will be available as a resource .
DMV's to check
Sys.Geo_replication_links--> Returns all replicas on the server
sys.dm_geo_replication_link_status--
Sys.dm_operation_status
sys.sp_wait_for_database_copy_sync
