PostgreSQL 12 High Availability Cookbook - Third Edition

Using an outage to test migration

While planned migrations are always preferred, sometimes hardware failures or server instability will introduce an aspect of surprise. If we had not used Pacemaker, a server crash would be a catastrophic event. Even if we had followed every chapter in this book this far and had Nagios, the full TIG monitoring stack, and email alerts galore, a DBA would need to be available to activate the alternate node.

If an outage occurred at night when everyone was sleeping, we would be faced with a worst-case scenario. The necessary personnel might not hear the alert for several minutes, and more time would be lost on triage and activation steps. Such an outage could extend from a few minutes to over an hour. So much ...