apache/hadoop · error · UnsupportedOperationException

Cannot getErasureCodingPolicy through a symlink to a non-Dis

Error message

Cannot getErasureCodingPolicy through a symlink to a non-DistributedFileSystem: {} -> {}

What it means

Error "Cannot getErasureCodingPolicy through a symlink to a non-DistributedFileSystem: {} -> {}" thrown in apache/hadoop.

Source

Thrown at hadoop-hdfs-project/hadoop-hdfs-client/src/main/java/org/apache/hadoop/hdfs/DistributedFileSystem.java:3481

  public ErasureCodingPolicy getErasureCodingPolicy(final Path path)
      throws IOException {
    statistics.incrementReadOps(1);
    storageStatistics.incrementOpCounter(OpType.GET_EC_POLICY);
    Path absF = fixRelativePart(path);
    return new FileSystemLinkResolver<ErasureCodingPolicy>() {
      @Override
      public ErasureCodingPolicy doCall(final Path p) throws IOException {
        return dfs.getErasureCodingPolicy(getPathName(p));
      }

      @Override
      public ErasureCodingPolicy next(final FileSystem fs, final Path p)
          throws IOException {
        if (fs instanceof DistributedFileSystem) {
          DistributedFileSystem myDfs = (DistributedFileSystem) fs;
          return myDfs.getErasureCodingPolicy(p);
        }
        throw new UnsupportedOperationException(
            "Cannot getErasureCodingPolicy through a symlink to a "
                + "non-DistributedFileSystem: " + path + " -> " + p);
      }
    }.resolve(this, absF);
  }

  /**
   * Retrieve all the erasure coding policies supported by this file system,
   * including enabled, disabled and removed policies, but excluding
   * REPLICATION policy.
   *
   * @return all erasure coding policies supported by this file system.
   * @throws IOException
   */
  public Collection<ErasureCodingPolicyInfo> getAllErasureCodingPolicies()
      throws IOException {
    statistics.incrementReadOps(1);
    storageStatistics.incrementOpCounter(OpType.GET_EC_POLICIES);

View on GitHub (pinned to 2add963021)

Solutions

1. Query the erasure coding policy on the direct HDFS path.
2. Resolve symlinks before calling getErasureCodingPolicy.

When it happens

Trigger: getErasureCodingPolicy is invoked through a symlink whose target is not a DistributedFileSystem, so no erasure coding policy is available.

Common situations: See trigger scenarios.

AI-assisted analysis of apache/hadoop@2add963021 (2026-08-22). Data as JSON: /api/errors/1f115de4296681bb. Report an issue: GitHub.