You can restore C and D from zero without having to shut off A (master server).
Just make a backup using --master-data=2 option
mysqldump -u MyUser -p --opt --master-data=2 --routines --databases MyDatabase > /pathtobackup/backup.sql
(During th backup the server will be up but the DB will be locked (all transactions will be processed after finish automatically.
That backup.sql contains a magic value... If you open it, will see the following line:
-- CHANGE MASTER TO MASTER_LOG_FILE='mysql-bin.000008', MASTER_LOG_POS=829650236;
So that's the magic, just restore that backup in C and set the master values as pointed.
Repeat from C to D.
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Ing. Jesús Alfredo Uzcanga
Twitter: @JesusUzcanga
We learn the 20% of what we HEAR,
the 50% of what we SEE,
the 80% of what we DO and
the 95% of what we TEACH.
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https://www.linkedin.com/in/jauzcanga/