If there is only one DC, can we still use EACH_QUORUM for write? We only have one DC now, but will build another one in future and like to use EACH_QUORUM when there are two. But like to know if it's good to use EACH_QUORUM with the current 1 DC.

And if there are two DCs but in some cases one whole DC cluster is down, does that mean all the writes are going to fail?