Yup - my db02 server lost a disk, and the array itself is corrupt (RAID5, yet corrupt data.) I was able to get the OS back online, but the corruption is severe. I have zero documentation about the mysql configuration, other than a copy of the /etc/my.cnf file from the failed host. (one small joy in this.)

1) How would I determine if it was in a m-s or m-m configuration?

2) Since I am lucky enough to have the /etc/my.cnf file, is there a clean way of restoring from the master?

3) Anyone have any other ideas as to what I should look for, in order to make sure what else needs to be put back in place? Backups are managed via scripting, from yet another system.


For M-M, both need to be masters and both need to be slaves. Those need


These should show something, even if not actively replicating at the moment:


If you can't run things on the broken machine, then I suggest you do

  • Clone the good machine's disk to the bad
  • Change my.cnf to have a different server_id
  • Turn on the two flags above
  • CHANGE MASTER ... on both -- to establish being a Slave, and provide the pwd for the replication 'user'.

Now you will have Master-Master. (There is not a lot of differences between M-S and M-M, so you may as well go for M-M.)

| improve this answer | |
  • If the my.cnf does not contain "log_slave_updates", then they are not in a M-M setup, correct? – Bee Kay Jan 24 '17 at 21:37
  • @RickJames would these 2 commands (show master and slave status) reveal the setup if they are run on the first, intact server? – ypercubeᵀᴹ Jan 24 '17 at 21:45

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