[Solved] Change NoOfReplicas

[Andreas Risch]

I'm new to this whole MySQL Cluster and now I need to change a productive server cluster.
The problem is there shouldn't really be a downtime at all.

The setup is the following:
3 Servers
1x ndb_mgmd on Server 1
1x mysqld and 1x ndbd on Server 2 (all Clients access this mysql)
1x mysqld and 1x ndbd on Server 3

New it should be the following:
3 Servers
1x ndb_mgmd with mysqld on Server 1
1x ndbd on Server 2
1x ndbd on Server 3


The problem that I have: How can I change the NoOfReplicas from 1 to 2?
The only thing I found out: make a mysqldump, recreate the whole cluster with NoOfReplicas=2 in the config and then import the dump again. But that takes too long. I could have a downtime of about 5min with this location.

You probably ask now: You only have 3 Servers, what happens when Server 1 crashes: Thats not that big of a deal. The only thing that is important right now: No data loss. But with NoOfReplicas=1 there will be dataloss, as far as I understood it.



Edited 2 time(s). Last edit at 01/16/2017 01:28AM by Andreas Risch.