Is there a way to synchronize mysql databases that are missing a few days worth of data I have a primary-primary MySQL server setup that is connected to a load balancer. At one point, a failure occurred to where the replication wasn't happening and data was being written to one server and not the other. We have since fixed the replication issue. However, both servers are missing data that the other server has due to the load balance switching.

Is there a way to sync the missing data between both devices?
This may be your best bet:
https://www.percona.com/doc/percona-toolkit/2.1/pt-table-sync.html

However, if you have inserted the same unique key (or AUTO_INCREMENT value) on both masters, there will be a mess.