[CASSANDRA-14557] Add default and required keyspace replication options

• Type: Improvement
• Status: Resolved
• Priority: Low
• Resolution: Fixed
• Fix Version/s: 4.1-alpha1, 4.1
• Component/s: Local/Config
• Labels: 4.0-feature-freeze-review-requested

Source Control Link

https://github.com/apache/cassandra/commit/5fdadb25f95099b8945d9d9ee11d3e380d3867f4

• Assignee: Sumanth Pasupuleti
• Reporter: Sumanth Pasupuleti

Authors

Sumanth Pasupuleti

Reviewers

Aleksei Zotov, Stefan Miklosovic

• Created: 03/Jul/18 22:02
• Updated: 27/May/22 19:25
• Resolved: 13/Oct/21 09:47

Description

Ending up with a keyspace of RF=1 is unfortunately pretty easy in C* right now - the system_auth table for example is created with RF=1 (to take into account single node setups afaict from CASSANDRA-5112), and a user can further create a keyspace with RF=1 posing availability and streaming risks (e.g. rebuild).

I propose we add two configuration options in cassandra.yaml:

1. default_keyspace_rf (default: 1) - If replication factors are not specified, use this number.
2. required_minimum_keyspace_rf (default: unset) - Prevent users from creating a keyspace with an RF less than what is configured

These settings could further be re-used to:

• Provide defaults for new keyspaces created with SimpleStrategy or NetworkTopologyStrategy (CASSANDRA-14303)
• Make the automatic token allocation algorithm interface more intuitive allowing easy use of the new token allocation algorithm.

At the end of the day, if someone really wants to allow RF=1, they simply don’t set the setting. For backwards compatibility the default remains 1 and C* would create with RF=1, and would default to current behavior of allowing any RF on keyspaces.

Issue Links

• is related to: CASSANDRA-17212 Migrate threshold for minimum keyspace replication factor to guardrails
• is related to: CASSANDRA-14303 Auto-expand replication_factor for NetworkTopologyStrategy
• relates to: CASSANDRA-17500 Create Maximum Keyspace Replication Factor Guardrail