A few days ago, we've had to stop every machine for some maintenance. Two of these were a MySQL master-slave. After the restart, the master didn't get the service back online and, due to the critical nature of the database, the slave took over, basically functioning as a normal, non-replicated service.
There were no changes to any of the my.cnf configuration files. The slave received various UPDATE and INSERT commands, so what will happen if I simply start the master back again? Will it manage to sync back? If not, how should I proceed?