We have an application at a customer’s site that has redundancy enabled. After a power failure on May 11th, the customer complained that hourly logged transaction group data was now showing up twice at the top of each hour. PCs are protected by UPS, but the power outage was longer than the UPS backup time.
Since this is an out of town job, I had issued with their IT department getting my remote desktop connection re-established. Finally got online today and noticed that data logged at the top of the hour, plus around another 1minute 45 seconds later , another transaction was logged.
Eventually traced problem to the Backup was running and logging data to the database as well, eventhough the Master was running.
Checking the status on the master, only the master node was displayed, checking status on the backup only the backup node was displayed
I had to log onto the Backup and toggle its mode from Backup ->Independant → Backup in order to stop it from logging to the database and have the status of Master → Backup show up in Status.
The attached snaphot shows the logged data and where I corrected the issue just before 16:00.
How does the backup node detect the master after a power failure? I have the Master Recovery set to Automatic.