We're carrying out a test of failover for our customer facing recursive DNS. There is no disruption expected, although of course because this is such a critical service we are creating an at risk PEW window. Should the test fail, it'll be immediately put back and any outage would only be expected to be a few seconds.
The test was successful, in that it showed the failover scenario we were testing works. It was good to do as it highlighted something we need to investigate. The at risk period is now over.
Work has been completed