1. I need to ensure that data is replicated to X places.
2. I need to *know* which places data was synchronously replicated to when the master goes down.
My entire point is that (1) alone is useless unless you also have (2). And do note that I'm talking about information on the replica, not on the master, since in any failure situation we don't have the old master around to check.
You might *think* you know, but given we are in this situation because of an unexpected failure, it seems strange to specifically avoid checking before you proceed.
Bacon not Aristotle.
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Simon Riggs http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services