Note that PostgreSQL 9.2 has been end of life for almost 5 years by now. If I were you I'd be a *lot* more worried about that than I would be about Bucardo.
I'm not saying Bucardo is good or bad, nor saying that I am not worried about a production system having PG 9.2. It's quite the opposite.. that's why we're working on this migration.
I'm saying that I do not have enough experience with Bucardo to have a bidirectional replication in place.
But that assumes that your customers are not shared in the same table
That is exactly my problem...
As long as you run pg_upgrade in link mode, diong so on a 1.5TB database is a very quick operation, normally completes in a couple of minutes including the ANALYZE step. This is a "destructive operation", so you can't go back if something goes wrong, but just keep an extra standby node around to fail over to if everything blows up and you have that covered.
I'll test this again, this time in link mode.
Lucas