We have clients in all our DCs. Rebuild has always been much faster for us than repairs. It operates as bootstrap by streaming data from only one source replica for each token range (need to do a cleanup if run multiple times). Repair is a different operation and is not supposed to be run on an empty node. It does more processing, merkle trees comparison, delete tombstones etc…
We use repairs when we add a DC as a new replication source to a Keyspace. — Cyril Scetbon > Assuming the rebuild is happening on a node in another DC, then there should > not be an issue if you are using LOCAL_ONE. If the node is in the local DC > (i.e., same DC as the client), I am inclined to think repair would be more > appropriate than rebuild but I am not 100% certain. > -- > > - John
