You know what it's like, you need to fail your AG over but is it safe to fail over? Perhaps you've clicked on 'failover' for the AG and there's a little green tick and no data loss reported... Or maybe you've checked out sys.dm_hadr_database_replica_cluster_states and 'is_failover_ready' is reporting a 1. So, you're cool to failover,... Continue Reading →
Availability Groups: When Your Synchronous Secondary isn’t Synchronous
During a recent DR scenario I came across a slight misinterpretation in how availability groups with replicas in synchronous commit behave. How An Availability Group With A Synchronous Secondary Should Behave Under Normal Circumstances Normally, if we've got a secondary replica in synchronous commit mode, our primary can't commit any transactions until that transaction has... Continue Reading →
Upgrading our Test lab from SQL 2016 to 2017 CTP with Always On Availability Groups
At SQLUndercover we decided it would be a good idea to not only upgrade our test lab but to treat it as if it were a live system carrying out an in place upgrade with minimal downtime, here's how we did it: Here is our very basic setup for this scenario, we have two availability... Continue Reading →