During the upgrade process both appliances will shut down and restart. During this time, when secondary and primary are both down and then come back up. The primary comes back up as normal but the secondary node will not turn on and postgres will not start.
Fails with the following message:
FATAL: hot standby is not possible because max_wal_senders = 8 is a lower setting than on the master server (its value was 10)
However both primary and secondary in the postgresql.conf file have max_wal_senders = 8. The secondary somehow is assuming that the primary's max_wal_senders should be 10 even though it's explicitly set to 8 in the conf files.
Tried upgrade the appliances and expected postgres to start up as normal.
Tried verifying the versions of postgres to make sure there is not an issue.
