I have few MySql absolutely isolated trees, each one of them has one master and few slaves.
For purposes of automation I need to set the same server_id to all masters (this will simplify the usage of pt-heartbeat which needs server_id). This should be perfectly fine since all trees are isolated.
I am wondering, if I change server_id on master, restart master, do I damage the replication? Of course there are will be a short brake of replication, but will this break replication completely?
The question is does changing server_id break replication completely, does it change positions in bin-log?
UPDATE: actually I don't have to restart mysql, I can just change it in console with SET GLOBAL server_id=xxx, in this case I don't need restart.
Best Answer
It should not break replication provided you do not choose a bad server_id. Here is why:
Given this server_id setup
Here is what happens with Replication
What happens if you set the Master's server_id to 2 ?
The only bad server_id to assign is the same server_id as the Slave. Other than that, Replication should not break.