apache/hadoop · error · UnsupportedOperationException

{} doesn't support unsetStoragePolicy

Error message

{} doesn't support unsetStoragePolicy

What it means

AbstractFileSystem.unsetStoragePolicy(Path) is a default stub that throws UnsupportedOperationException naming the subclass. Unsetting (reverting to inherited/default policy) is HDFS-only; filesystems without a storage-policy engine keep the stub. The error indicates scheme-level non-support, not a missing or already-unset policy.

Source

Thrown at hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/AbstractFileSystem.java:1547

   * @param policyName the name of the target storage policy. The list
   *                   of supported Storage policies can be retrieved
   *                   via {@link #getAllStoragePolicies}.
   * @throws IOException raised on errors performing I/O.
   */
  public void setStoragePolicy(final Path path, final String policyName)
      throws IOException {
    throw new UnsupportedOperationException(getClass().getSimpleName()
        + " doesn't support setStoragePolicy");
  }


  /**
   * Unset the storage policy set for a given file or directory.
   * @param src file or directory path.
   * @throws IOException raised on errors performing I/O.
   */
  public void unsetStoragePolicy(final Path src) throws IOException {
    throw new UnsupportedOperationException(getClass().getSimpleName()
        + " doesn't support unsetStoragePolicy");
  }

  /**
   * Retrieve the storage policy for a given file or directory.
   *
   * @param src file or directory path.
   * @return storage policy for give file.
   * @throws IOException raised on errors performing I/O.
   */
  public BlockStoragePolicySpi getStoragePolicy(final Path src)
      throws IOException {
    throw new UnsupportedOperationException(getClass().getSimpleName()
        + " doesn't support getStoragePolicy");
  }

  /**
   * Retrieve all the storage policies supported by this file system.

View on GitHub (pinned to 2add963021)

Solutions

  1. Restrict unsetStoragePolicy calls to hdfs:// paths.
  2. Use DistributedFileSystem.unsetStoragePolicy / `hdfs dfsadmin -unsetStoragePolicy` for the supported path.
  3. Gate by URI scheme in shared code.
  4. Catch UnsupportedOperationException and skip when the store has no policy concept.

Example fix

// before
fc.unsetStoragePolicy(path); // throws on unsupported scheme

// after
if ("hdfs".equals(path.toUri().getScheme())) {
  fc.unsetStoragePolicy(path);
}
Defensive patterns

Strategy: validation

Validate before calling

static boolean policyOpsSupported(Path p) {
  return "hdfs".equals(p.toUri().getScheme());
}

Try / catch

try {
  fc.unsetStoragePolicy(path);
} catch (UnsupportedOperationException e) {
  // nothing to unset: store has no policies
}

Prevention

When it happens

Trigger: FileContext.unsetStoragePolicy(src) against non-HDFS schemes; policy-management code that unsets policies during directory reorganization run on local or object-store paths.

Common situations: Policy lifecycle scripts (set on ingest, unset on archive) run against the wrong cluster/endpoint; test environments with file:// defaultFS; viewfs mounts to non-HDFS targets.

Related errors

AI-assisted analysis of apache/hadoop@2add963021 (2026-08-22). Data as JSON: /api/errors/bb193d662a6ee3d5. Report an issue: GitHub.