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What are the benefits If I enable Namenoe HA without auto failover vs no namenode HA?

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What are the benefits If I enable Namenoe HA without auto failover vs no namenode HA?

Contributor

It makes perfect sense if we enable auto failover in a NN HA configuration. But if I just want to enable NN HA without enablhing auto failover, does it provide any advantage comparing single namenode + secondary namnode?

 

NOTE: in my non-ha configuration, I have mounted one of my nn dir to NFS by which provides fault tolerance.

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Re: What are the benefits If I enable Namenoe HA without auto failover vs no namenode HA?

Cloudera Employee

Hi keagles,

 

It can be still useful to do manual failover in some cases. For example, you would like to do some HW/OS maintenance on the active datanode - you can fail over manually to the other NN without distrupting running processes on the cluster.

 

Also, you can do configuration changes to the NN in the same way. Change config, then restart the Standby NN, it will start with the new configuration, fail over, then restart the other one. See, you updated your NN's settings without the need to do a full cluster stop.

 

These are not possible with a non-HA configuration.

 

 

cheers,

zegab

 

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Re: What are the benefits If I enable Namenoe HA without auto failover vs no namenode HA?

Cloudera Employee

Hi keagles,

 

It can be still useful to do manual failover in some cases. For example, you would like to do some HW/OS maintenance on the active datanode - you can fail over manually to the other NN without distrupting running processes on the cluster.

 

Also, you can do configuration changes to the NN in the same way. Change config, then restart the Standby NN, it will start with the new configuration, fail over, then restart the other one. See, you updated your NN's settings without the need to do a full cluster stop.

 

These are not possible with a non-HA configuration.

 

 

cheers,

zegab