Provided values are not recommended for (warned values are…

Error message

Provided values %s are not recommended for %s (warned values are: %s)

What it means

Values.guard intersects the provided values with the guardrail's 'warned' set. When any provided value falls in the warned set, this warning is emitted but the operation proceeds. It signals 'not recommended' usage without blocking it.

Solutions

Replace the warned values with recommended alternatives.
If usage is intentional, acknowledge the warning or tune the guardrail's warned threshold in cassandra.yaml.
Escalate the guardrail to 'failed' in configuration if the values must never be used.

Example fix

// before
CREATE KEYSPACE ks WITH replication = {'class': 'SimpleStrategy', 'replication_factor': 1};
// after (multi-DC cluster)
CREATE KEYSPACE ks WITH replication = {'class': 'NetworkTopologyStrategy', 'dc1': 3};

Defensive patterns

Strategy: validation

Validate before calling

Set<String> provided = parseOptions(statement);
Set<String> warned = guardrailsConfig.warnedValuesFor(what);
if (!Collections.disjoint(provided, warned)) {
    logger.warn("Non-recommended options in use: {}", Sets.intersection(provided, warned));
}

Prevention

Follow version-specific best-practice option lists.
Run guardrail checks in CI schema tests.
Re-audit warned configurations after upgrades.

When it happens

Trigger: An operation supplies values configured in the guardrail's warned list (e.g. discouraged replication strategies, table options, feature settings) for the guardrail's 'what' category; also exercised by test harnesses (testValuesWarned).

Common situations: Clusters using settings flagged discouraged after an upgrade; schema copied from reference clusters using non-recommended options; capacity planners flagging dangerous defaults.

Understand the failure class

Background: "is deprecated and will be removed" — deprecation warnings for old API names, keywords, and options, and how to migrate before the removal release — this error's family across 29 libraries.

Related errors

AI-assisted analysis of apache/cassandra@88fd0f6a0e (2026-09-10). Data as JSON: /api/errors/b49b487232558285. Report an issue: GitHub.

Appendix: source

Thrown at src/java/org/apache/cassandra/db/guardrails/Values.java:127

        Set<T> disallowed = disallowedValues.apply(state);
        Set<T> toDisallow = Sets.intersection(values, disallowed);
        if (!toDisallow.isEmpty())
            fail(format("Provided values %s are not allowed for %s (disallowed values are: %s)",
                        toDisallow.stream().sorted().collect(Collectors.toList()), what, disallowed), state);

        Set<T> ignored = ignoredValues.apply(state);
        Set<T> toIgnore = Sets.intersection(values, ignored);
        if (!toIgnore.isEmpty())
        {
            warn(format("Ignoring provided values %s as they are not supported for %s (ignored values are: %s)",
                        toIgnore.stream().sorted().collect(Collectors.toList()), what, ignored));
            toIgnore.forEach(ignoreAction);
        }

        Set<T> warned = warnedValues.apply(state);
        Set<T> toWarn = Sets.intersection(values, warned);
        if (!toWarn.isEmpty())
            warn(format("Provided values %s are not recommended for %s (warned values are: %s)",
                        toWarn.stream().sorted().collect(Collectors.toList()), what, warned));
    }
}

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