An organization suffered a critical failure of its primary datacenter and made the decision to switch to the DR site. After one week of using the DR site, the p...

An organization suffered a critical failure of its primary datacenter and made the decision to switch to the DR site. After one week of using the DR site, the primary datacenter is now ready to resume operations.
Which of the following is the MOST efficient way to bring the block storage in the primary datacenter up to date with the DR site?