Do you have a monitor on your PG boxen? I've got them set to warn at 50% full, due to table update issues mentioned. For huge/destructive updates we run first

Do you have a monitor on your PG boxen? I've got them set to warn at 50% full, due to table update issues mentioned. For huge/destructive updates we run first pass on a clone and generate a pg_dump of DB or at least specific tables before the operation on Live