Continuous Replication-Block Mode.
Continuous replication is a feature added in Exchange 2010 SP1.
►In really simple words, In block mode the transaction is shipped as it is written
into memory unlike the file mode when a entire log is shipped after
been written and closed. Isn’t this a greate feature to add, i was just wondering
why did it take so much time for the exchange product team to add thsi feature.
►Continuous replication–block mode reduces the exposure of data loss on failover by
replicating all logs writes to the passive database copies in parallel to writing
them locally. In other words, block mode replicates the transactions to the database
copies as they are being written to the active local transaction log files.
Now what are the settings to be configured to make this work:
►Nothing 
Enabling and disabling block mode is done automatically by the log copy process
by database. Block mode will automatically become active when continuous replication file mode
is up-to-date with the database copies.
►The replication transport is the same when granular replication is enabled or disabled. The benefit
of block mode is that it can dramatically reduce the latency between the active copy and the passive
copy while also reducing the possibility of data loss during a failover and the time it takes to
perform a switchover.
