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a.gheshlaghy_177282 avatar image
a.gheshlaghy_177282 asked ·

Should NodeSync be enabled on system keyspaces?

Hi
it is mentioned in datastax documentation(https://docs.datastax.com/en/security/6.7/security/secSystemKeyspace.html) that to change replication class from simple to networkTopology strategy and increase the RF for system_auth and dse_security keyspaces. Should we do this to below keyspaces which are not user defined?
-system_traces
-dse_perf
-system_distributed
-dse_lease

And also, is it a good practice to enable nodesync on below keyspaces ?
-system_auth
-dse_security
-system_traces
-dse_perf
-system_distributed
-dse_leases




replicationnodesync
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1 Answer

bettina.swynnerton avatar image
bettina.swynnerton answered ·

Hi,

the four system keyspaces that you listed are helper keyspaces that are relevant for certain functions only.

dse_leases is a keyspace that is used for Spark master election. Unless you are using DSE Analytics in your cluster, you won't need to change the replication strategy for dse_leases. If you are using DSE Analytics, you have to change the replication strategy too, or you will run into issues with Spark master election and Spark job execution.

If you use DSE Analytics, check this document for replication settings:

https://docs.datastax.com/en/dse/6.7/dse-dev/datastax_enterprise/analytics/settingReplFactorAnalyticsKeyspaces.html

system_distributed is a keyspace that stores repair information. In general there is no need to change the default replication factor.

system_traces is a keyspace that stores tracing data, and only if tracing is enabled. In general there is no need to change the default replication factor, unless you have a special requirement during your tracing efforts.

dse_perf is the keyspace used for the DSE performance service.

By default, DataStax Enterprise writes performance metrics data with consistency level ONE and writes are performed asynchronously. Unless you using the performance service extensively, you might not need to change the replication factor, it depends on your requirements.

https://docs.datastax.com/en/dse/6.7/dse-admin/datastax_enterprise/mgmtServices/performance/configPerformanceService.html

You can enable nodesync on all these keyspaces. In DSE 6.8, nodesync is enabled on all keyspaces by default.

I hope this helps!

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