Just to be pedantically clear: you must lock a set of old tlogs such that it overlaps with any quorum of old tlogs that could be used to commit before starting a new set of tlogs. The new tlogs and old tlogs have no quorum interactions.
Just to be pedantically clear: you must lock a set of old tlogs such that it overlaps with any quorum of old tlogs that could be used to commit before starting a new set of tlogs. The new tlogs and old tlogs have no quorum interactions.