This came up in discussion of
CASSANDRA-11687. nodetool rebuild was failing in a dtest. pauloricardomg explained:
CASSANDRA-11848the local node could be considered a source, while now sources are restricted only to dc2, so since system_auth uses SimpleStrategy depending on the token arrangement there could or not be sources from dc2. Fix is to either use -Dcassandra.consistent.rangemovement=false or update system_auth to use NetworkTopologyStrategy with 2 dcs..
This is, at the very least, a UX bug. When rebuild fails, it fails with
nodetool: Unable to find sufficient sources for streaming range (-3287869951390391138,-1624006824486474209] in keyspace system_auth with RF=1.If you want to ignore this, consider using system property -Dcassandra.consistent.rangemovement=false.
which suggests that a user should give up consistency guarantees when it's not necessary.