DataStax Academy FAQ

DataStax Academy migrated to a new learning management system (LMS) in July 2020. We are also moving to a new Cassandra Certification process so there are changes to exam bookings, voucher system and issuing of certificates.

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question

raktim.0526_188212 avatar image
raktim.0526_188212 asked ·

What is the right way of restarting DSE after configuration changes?

Currently I have a data center with 3 nodes. After I make changes to cassandra.yaml file, I run the following commands on each node to restart.

nodetool drain 
sudo service dse stop
sudo service dse start

This throws an error. Which can be resolved by deleting the commit-logs, saved-caches and data from /var/lib/cassandra.

But I do not want to delete these files. Why am I not able to restart DSE without having to remove these files? I am losing all my data in this process.

Would really appreciate if someone could head me in the right direction with respect to restarting DSE.

dse
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1 Answer

Erick Ramirez avatar image
Erick Ramirez answered ·

Personally, I always recommend doing what you outlined:

  1. Run nodetool drain to flush all memtables to disk so there are no commit logs to replay on startup.
  2. Cleanly shutdown DSE (or Cassandra).
  3. Start DSE (or Cassandra).

Having said that, something else is wrong in your case. There is no scenario in DSE or Cassandra that requires you to delete data in order to restart the service.

I suspect that this is more a problem with the configuration changes you've made that is not valid once a node has been started such as attempting to change the cluster_name which is not allowed.

If you post a new question with the following details, I'd be happy to tell you what went wrong:

  • configuration changes including old and new values
  • full error message + full stack trace
  • DSE version

Cheers!

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