apache/cassandra · error · ConfigurationException

paxos_cache_size option was set incorrectly to '<value>', su

Error message

paxos_cache_size option was set incorrectly to '<value>', supported values are <integer> >= 0.

What it means

ConfigurationException raised in applySimpleConfig when the paxos_cache_size yaml value cannot be parsed as the expected numeric/auto form (NumberFormatException caught around its parsing, mirroring the counter_cache_size guard shown). It fires at startup or config apply when the value's format is invalid, not when the size is merely large.

Source

Thrown at src/java/org/apache/cassandra/config/DatabaseDescriptor.java:1044

        catch (NumberFormatException e)
        {
            throw new ConfigurationException("counter_cache_size option was set incorrectly to '"
                                             + (conf.counter_cache_size != null ? conf.counter_cache_size.toString() : null) + "', supported values are <integer> >= 0.", false);
        }

        try
        {
            // if paxosCacheSizeInMiB option was set to "auto" then size of the cache should be "min(1% of Heap (in MB), 50MB)
            paxosCacheSizeInMiB = (conf.paxos_cache_size == null)
                                  ? Math.min(Math.max(1, (int) (Runtime.getRuntime().totalMemory() * 0.01 / 1024 / 1024)), 50)
                                  : conf.paxos_cache_size.toMebibytes();

            if (paxosCacheSizeInMiB < 0)
                throw new NumberFormatException(); // to escape duplicating error message
        }
        catch (NumberFormatException e)
        {
            throw new ConfigurationException("paxos_cache_size option was set incorrectly to '"
                                             + conf.paxos_cache_size + "', supported values are <integer> >= 0.", false);
        }

        try
        {
            // if accordCacheSizeInMiB option was set to "auto" then size of the cache should be "max(10% of Heap (in MB), 1MB)
            accordCacheSizeInMiB = (conf.accord.cache_size == null)
                                  ? Math.max(1, (int) ((Runtime.getRuntime().totalMemory() * 0.10) / 1024 / 1024))
                                  : conf.accord.cache_size.toMebibytes();

            if (accordCacheSizeInMiB < 0)
                throw new NumberFormatException(); // to escape duplicating error message
        }
        catch (NumberFormatException e)
        {
            throw new ConfigurationException("accord.cache_size option was set incorrectly to '"
                                             + conf.accord.cache_size + "', supported values are <integer> >= 0.", false);
        }

View on GitHub (pinned to 88fd0f6a0e)

Solutions

  1. Set paxos_cache_size to a plain non-negative integer of MiB, e.g. 50
  2. Use 'auto' for min(1% of heap, 50MiB)
  3. Remove the key to accept the default
  4. Restart the node

Example fix

// before (cassandra.yaml)
paxos_cache_size: 1MB
// after
paxos_cache_size: 50
// or
paxos_cache_size: auto
Defensive patterns

Strategy: validation

Validate before calling

String v = yaml.get("paxos_cache_size");
if (v != null && !v.equals("auto") && Long.parseLong(v) < 0) throw new IllegalArgumentException(v);

Try / catch

try { DatabaseDescriptor.daemonInitialization(); }
catch (ConfigurationException e) { LOG.fatal(e.getMessage()); System.exit(1); }

Prevention

When it happens

Trigger: Node startup with paxos_cache_size in cassandra.yaml that is negative, unit-suffixed, or otherwise not a bare integer.

Common situations: Copying the key name from a different Cassandra version where it did not exist and supplying a units string; typos like '1OO' with a letter O; negative values.

Understand the failure class

Background: "Invalid value" and "allowed values are" config errors: what your library rejected and how to fix it — this error's family across 41 libraries.

Related errors

AI-assisted analysis of apache/cassandra@88fd0f6a0e (2026-09-10). Data as JSON: /api/errors/fd1fab17e9340a7a. Report an issue: GitHub.