apache/cassandra · error · RuntimeException

You can not store Async-Profiler results into a data…

Error message

You can not store Async-Profiler results into a data directory of Cassandra.

What it means

maybeCreateProfilesLogDir also rejects placing the Async-Profiler log directory under any Cassandra data file location (data dirs from StorageService.getAllDataFileLocations). Profiler results inside a data directory would pollute SSTable storage and can interfere with operations like snapshots or cleanup, so a RuntimeException is thrown.

Solutions

Choose a profiler log directory outside all data_file_directories entries
Keep profiling output on a separate filesystem/mount from data and commitlog
Audit the resolved absolute path prefix against getAllDataFileLocations before configuring

Example fix

// before
async_profiler_dir: /var/lib/cassandra/data/prof
// after
async_profiler_dir: /var/log/cassandra/async-profiler

Defensive patterns

Strategy: validation

Validate before calling

String dir = Path.of(profilerLogDir).toAbsolutePath().toString();
boolean inDataDir = StorageService.instance.getAllDataFileLocations().stream().anyMatch(dir::startsWith);
if (inDataDir) throw new IllegalArgumentException("profiler log dir must not be inside a data directory");

Try / catch

try { svc.apply(cmd, file); } catch (RuntimeException e) { if (e.getMessage().contains("data directory of Cassandra")) { log.error("move profiler log dir out of data_file_directories"); throw e; } throw e; }

Prevention

Keep profiler output off data_file_directories mounts
Use absolute, dedicated paths (e.g. /var/log/cassandra/async-profiler)
Check path prefixes against getAllDataFileLocations during provisioning

When it happens

Trigger: Configuring the profiler log dir at or beneath a data_file_directories entry and then triggering instance(), apply(), list(), fetch(), or purge().

Common situations: Single-volume setups where everything lives under /var/lib/cassandra/data; operators assuming any Cassandra-owned directory is acceptable; automated provisioning that reuses the data dir for logs.

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/be90f47167007e26. Report an issue: GitHub.

Appendix: source

Thrown at src/java/org/apache/cassandra/service/AsyncProfilerService.java:439

    }

    private static void maybeCreateProfilesLogDir()
    {
        String dir = new File(logDir).toAbsolute().toString();

        if ((DatabaseDescriptor.getCommitLogLocation() != null && dir.startsWith(DatabaseDescriptor.getCommitLogLocation())) ||
            (DatabaseDescriptor.getAccordJournalDirectory() != null && dir.startsWith(DatabaseDescriptor.getAccordJournalDirectory())) ||
            dir.startsWith(DatabaseDescriptor.getHintsDirectory().absolutePath()) ||
            (DatabaseDescriptor.getCDCLogLocation() != null && dir.startsWith(DatabaseDescriptor.getCDCLogLocation())) ||
            (DatabaseDescriptor.getSavedCachesLocation() != null && dir.startsWith(DatabaseDescriptor.getSavedCachesLocation())))
        {
            throw new RuntimeException("You can not store Async-Profiler results into system Cassandra directory.");
        }

        for (String location : StorageService.instance.getAllDataFileLocations())
        {
            if (dir.startsWith(location))
                throw new RuntimeException("You can not store Async-Profiler results into a data directory of Cassandra.");
        }

        try
        {
            new File(logDir).createDirectoriesIfNotExists();
        }
        catch (Throwable t)
        {
            throw new RuntimeException("Unable to create directory " + logDir);
        }
    }

    private void validateStartParameters(Map<String, String> parameters)
    {
        if (!ASYNC_PROFILER_START_PARAMS.equals(parameters.keySet()))
        {
            throw new IllegalArgumentException("Wrong parameters passed to start async profiler method. Passed parameters" +
                                               " should be: " + ASYNC_PROFILER_START_PARAMS);

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