Troubleshooting ElastiCenter HA

Assume that you have installed CloudByte ElastiStor in the ElastiCenter HA mode. If the primary Node Node1 and the associated ElastiCenter goes offline, the secondary Node Node2 takes up the functionality of both the Node and the associated ElastiCenter (which now acts as the primary). The following two scenarios explain the issues that you might encounter.

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Scenario 1: Primary Node is down.

Node Node1 is down, Node Node2 takes over, and then you want to bring up Node Node1.

So,

  • In this scenario, Node Node1 is down.
  • Node Node2 has taken over and is the primary Node.
  • You are trying to bring up Node Node1 so that it can be the secondary.

Do the following:

  1. Bring up Node Node1 online and move it to Available state. For details, see Making a Node available.
    Now Node Node1 acts as the secondary Node.
  2. Confirm the step 2 in the ElastiCenter HA page in the Admin pane of ElastiCenter (Admin > ElastiCenter HA).

Scenario 2: Primary Node and secondary Node are both down.

Node Node1 is down, Node Node2 takes over, and then Node Node2 goes down.

So,

  • In this scenario, both Node Node1 and Node Node2 are down.
  • Both Node Node1 and Node Node2 were in the primary state when they went down.
  • Currently, Node Node2 is in a standalone state as there is no other Node to take over.

To bring back the setup,

  1. Bring the Node Node2 online.
  2. Move the Node Node2 to the Available state. All the services are automatically restarted.
  3. (After the Node Node2 is up and running) Bring up Node Node1 online and move it to the Available state. For details, see Making a Node available.
    Now Node Node1 acts as the secondary Node.
  4. Confirm the step 4 in the ElastiCenter HA page in the Admin pane of ElastiCenter (Admin > ElastiCenter HA).

Note: Since both the Nodes in downtime were in the primary state, the Node that you bring up first will become the primary. There might be an associated data loss.