> Yes, but the region server now has 2X the number of WAL(s) to replicate and
> could suffer higher replication lag as a result...
In my experience this hasn't been an issue. Keep in mind that the RS
will only replicate what's in the queue when it was recovered and
nothing more. It means you have one more thread reading from a likely
remote disk (low penalty), then it has to build its own set of edits
to replicate (unless you are already severly CPU contented that won't
be an issue), then you send those edits to the other cluster (unless
you are already filling that machine's pipe, it won't be an issue).
Was there anything you were thinking about? You'd rather spread those
logs to a bunch of machines?