MySQLcluster configuration

Question

I have installed MySQL cluster (NDB 7.3 ) with

• 1 management node
• 4 data nodes
• 3 sql node.

I have 4 partitions and two node groups. I have couple of questions.

1. Can i view data stored in each data node separately?

2. Where can i find the data sync logs?

3. is it possible to have two node groups with same data ie with partitions data is splitted and stored among node groups?

   tell me if there is a way to store same data among node groups, Currently my cluster wont work if a node group (2 nodes goes down).

4. when a node group goes down , others nodes restarts and whole cluster goes down. Is there a way to stop it and operate with other node groups.

Answer 1

I have found answers for my questions. All these fits with community supported MySQL cluster.

1 We cant view the data stored in a single data node separately. but we can see the number of rows stored per partition.When a query is given, Based on the partition info cluster finds the data nodes and gets output from data nodes and displays collectively. Thats why the order of rows differs each time if we execute the same query. please node that the overall data is same and only order changes.

2 I think we cant find the sync logs but we can find the amount of data updated in the data node when we replace it. Query will be success only if write is success and synced. so we don't need to worry about data syncing. when we replace a data node, it comes to online only after all data is synced.

3 Currently two node per node group is supported.

4 If a node group goes down, Cluster will stop working. This happens because a part of data is in a node group. So its a expected behavior.