apache/hadoop · error · IOException

Failed to create ${filePath}

Error message

Failed to create ${filePath}

What it means

Error "Failed to create ${filePath}" thrown in apache/hadoop.

Source

Thrown at hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/fsdataset/impl/PmemVolumeManager.java:459

   * @param volumeIndex   The index of pmem volume where a replica will be
   *                      cached to or has been cached to.
   *
   * @param key           The replica's ExtendedBlockId.
   *
   * @return              A path to which the block replica is mapped.
   */
  public String idToCacheFilePath(Byte volumeIndex, ExtendedBlockId key)
      throws IOException {
    final String cacheSubdirPrefix = "subdir";
    long blockId = key.getBlockId();
    String bpid = key.getBlockPoolId();
    int d1 = (int) ((blockId >> 16) & 0x1F);
    int d2 = (int) ((blockId >> 8) & 0x1F);
    String parentDir = pmemVolumes.get(volumeIndex) + "/" + bpid;
    String subDir = cacheSubdirPrefix + d1 + "/" + cacheSubdirPrefix + d2;
    File filePath = new File(parentDir, subDir);
    if (!filePath.exists() && !filePath.mkdirs()) {
      throw new IOException("Failed to create " + filePath.getPath());
    }
    return filePath.getAbsolutePath() + "/" + idToCacheFileName(key);
  }

  /**
   * The cache file path is pmemVolume/BlockPoolId/subdir#/subdir#/BlockId.
   */
  public String getCachePath(ExtendedBlockId key) throws IOException {
    Byte volumeIndex = blockKeyToVolume.get(key);
    if (volumeIndex == null) {
      return  null;
    }
    return idToCacheFilePath(volumeIndex, key);
  }

  @VisibleForTesting
  Map<ExtendedBlockId, Byte> getBlockKeyToVolume() {
    return blockKeyToVolume;

View on GitHub (pinned to 2add963021)

Solutions

1. Check permissions and free space on the pmem volume; create the parent directories if missing.
2. Verify the pmem device is mounted and healthy.

When it happens

Trigger: Pmem block caching when the backing cache file cannot be created on the pmem volume.

Common situations: See trigger scenarios.

AI-assisted analysis of apache/hadoop@2add963021 (2026-08-22). Data as JSON: /api/errors/064c332f47dfaa5a. Report an issue: GitHub.