Hi Nick
1. Take Backup.
2. Migrate the snitch. Refer
https://docs.datastax.com/en/cassandra-oss/3.x/cassandra/operations/opsSwitchSnitch.html
and
https://dba.stackexchange.com/questions/314862/how-do-i-change-the-cassandra-topology-snitch-in-a-multi-az-cluster
3. For altering the keyspace, run alter keyspace command as
ALTER KEYSPACE keyspace_name WITH REPLICATION = {'class':
'NetworkTopologyStrategy', '<datacentername>': 3};
4. Run repair if I am not mistaken should not be required for single DC.
Refer
https://docs.datastax.com/en/cassandra-oss/3.0/cassandra/operations/opsChangeKSStrategy.html
5. Test on a test environment first before applying on production.
Regards
Manish
On Thu, Jul 17, 2025 at 1:03 PM Nick Jonas <jonas.nick0786...@gmail.com>
wrote:
> Hi Community,
>
> We currently have a 3-node Cassandra 3.11 production cluster that was
> initially set up with the following configuration:
>
> -
>
> *Snitch:* endpoint_snitch: SimpleSnitch
> -
>
> *Keyspace replication:* {'class': 'SimpleStrategy',
> 'replication_factor': '3'}
>
> Unfortunately, this setup was not ideal for a production environment, and
> we're now looking to correct it. Specifically, we want to:
>
> 1.
>
> *Switch to a more appropriate snitch* (e.g.,
> GossipingPropertyFileSnitch)
> 2.
>
> *Update keyspaces to use* NetworkTopologyStrategy
>
> I would appreciate any advice on the best practices for making these
> changes in a running production cluster. My main concerns are:
>
> -
>
> What is the safest order of operations?
> -
>
> Will switching the snitch or replication strategy cause any *data loss
> or availability issues*?
> -
>
> Do we need to perform any additional steps (e.g., full repair, rolling
> restart, etc.)?
> -
>
> Are there specific * known issues* when migrating from SimpleSnitch +
> SimpleStrategy to a production-grade setup?
>
> Thanks in advance for your guidance!
>
