I'm assuming this is somewhat related to your previous question on
cross-DC replication. This is not an ideal set up as mentioned there.
If the replica lags then it will fall out of the "in-sync-replica"
set. You could tune parameters that effectively allow a high (but
bounded over time) lag between the replica and the leader. There is no
buffer per se - the replicas just keep fetching from the leader (which
would have appended the messages to its log).
If your producer has acks set to -1 (which means wait until all
replicas in ISR have received the message) it would slow down your
producer considerably. (You could use acks = 1 in that case though but
with weaker guarantees - i.e., your message could be lost in failure
On Fri, Jun 28, 2013 at 5:41 PM, Yu, Libo <[EMAIL PROTECTED]> wrote: