A method involves generating a block-level write operation, which causes a
value to be written to a primary volume, and generating information
indicative of whether any of the block-level write operation should be
transferred to a secondary site during replication of data in the primary
volume. The information can indicate that all, part, or none of the
block-level write operation should be transferred to the secondary site.
If the information indicates that less than all of the block-level write
operation should be transferred to a secondary site, the information can
also indicate that logical information associated with the block-level
write operation should be transferred to the secondary site instead of
transferring the value being written by the block-level write operation.