Mysql – Why there is a start (*) after Nodegroup:0 in MySQL cluster? What does it means


I am new to MySQL and MySQL cluster setup. However going through several blogs and Web links I've finally able to manage the cluster up and running. I have 1 management, 1 SQL and 3 data nodes (currently without any replicated SQL or data nodes as I have set NoOfReplicas=1 in the config.ini file). After running ndb_mgm> show I can see there is a start just after the first data node, what does it means? I searched over google but didn't find any proper answer. Kindly help.

ndb_mgm> show

Cluster Configuration

[ndbd(NDB)] 3 node(s)

id=3 @ (mysql-5.5.34 ndb-7.2.14, Nodegroup: 0, *)

id=4 @ (mysql-5.5.34 ndb-7.2.14, Nodegroup: 1)

id=5 @ (mysql-5.5.34 ndb-7.2.14, Nodegroup: 2)

[ndb_mgmd(MGM)] 1 node(s)

id=1 @ (mysql-5.5.34 ndb-7.2.14)

[mysqld(API)] 1 node(s)

id=6 @ (mysql-5.5.34 ndb-7.2.14)

Best Answer

It shows which node is master. It is internal thing and probably the only visible effect of it is when exactly half of the nodes goes down. Then if one of the remaining nodes is master - cluster keeps working. If not - cluster aborts.

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