A member can crash permanently and then be unable to recover from the failure. In that case, restart process cannot be completed since some of the members do not start or fail to load their own data. In that case, you can force the cluster to clean its persisted data and make a fresh start. This process is called force start.
Assume the following which is a valid scenario to use force start:
- You have a cluster consisting of members A and B which is initially stable.
- Cluster transitions into
FROZENorPASSIVEstate. - Cluster gracefully shuts down.
- Member A restarts, but member B does not.
- Member A uses its Hot Restart data to initiate the Hot Restart procedure.
- Since it knows the cluster originally contained member B as well, it waits for it to join.
- This never happens.
- Now you have the choice to Force Start the cluster without member B.
- Cluster discards all Hot Restart data and starts empty.
You can trigger the force start process using the Management Center, REST API and cluster management scripts.
Please note that force start is a destructive process, which results in deletion of persisted Hot Restart data.
Please refer to the Hot Restart functionality of the Management Center to learn how you can perform a force start using the Management Center.