apache/hadoop · error · IOException

Cannot create directory {curDir}

Error message

Cannot create directory {curDir}

What it means

The second guard in Storage.StorageDirectory.clearDirectory(): after successfully deleting current/, curDir.mkdirs() must recreate it, and failure throws IOException('Cannot create directory <curDir>'). This is a plain filesystem failure — the parent must be writable and the path must be free.

Source

Thrown at hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/common/Storage.java:447

     * Derived storage is responsible for setting specific storage values and
     * writing the version file to disk.
     * 
     * @throws IOException
     */
    public void clearDirectory() throws IOException {
      File curDir = this.getCurrentDir();
      if (curDir == null) {
        // if the directory is null, there is nothing to do.
        return;
      }
      if (curDir.exists()) {
        File[] files = FileUtil.listFiles(curDir);
        LOG.info("Will remove files: {}", Arrays.toString(files));
        if (!(FileUtil.fullyDelete(curDir)))
          throw new IOException("Cannot remove current directory: " + curDir);
      }
      if (!curDir.mkdirs()) {
        throw new IOException("Cannot create directory " + curDir);
      }
      if (permission != null) {
        try {
          Set<PosixFilePermission> permissions =
              PosixFilePermissions.fromString(permission.toString());
          Files.setPosixFilePermissions(curDir.toPath(), permissions);
        } catch (UnsupportedOperationException uoe) {
          // Default to FileUtil for non posix file systems
          FileUtil.setPermission(curDir, permission);
        }
      }
    }

    /**
     * Directory {@code current} contains latest files defining
     * the file system meta-data.
     * 
     * @return the directory path

View on GitHub (pinned to 2add963021)

Solutions

1. Check parent directory permissions/ownership for the daemon user (chown/chmod the storage root)
2. Remove any non-directory file occupying the current path
3. Free space and confirm the mount is read-write (df -h, mount), then retry the operation

Example fix

# before
df -h /dfs/nn   # 100% full, or root-owned

# after
sudo chown -R hdfs:hdfs /dfs/nn && sudo chmod 755 /dfs/nn
df -h /dfs/nn   # space available
sudo -u hdfs hdfs namenode -format

File curDir = sd.getCurrentDir();
File parent = curDir.getParentFile();
if (!parent.canWrite()) throw new IOException("No write permission on " + parent);
if (curDir.exists() && !curDir.isDirectory()) throw new IOException(curDir + " is a file");
if (parent.getUsableSpace() < MIN_FREE_BYTES) throw new IOException("Insufficient space under " + parent);
sd.clearDirectory();

try {
  sd.clearDirectory();
} catch (IOException e) {
  if (e.getMessage().startsWith("Cannot create directory")) {
    throw new IOException("Fix permissions/space on parent of " + sd.getCurrentDir(), e);
  } else throw e;
}

When it happens

Trigger: Format/rollback/finalize where current/ was deleted but recreation fails: no write permission on the parent directory, a non-directory file occupies the path, the filesystem is read-only, or the disk is full.

Common situations: Storage dir owned by root while the daemon runs as hdfs; a leftover file named 'current'; read-only mount after disk errors; full data disk on a DataNode.

Related errors

• Cannot remove current directory: {curDir}
• Cannot create directory {rootPath}
• Can't format the storage directory because the current direc
• Failed to delete {dir}
• Unable to download to any storage directory

AI-assisted analysis of apache/hadoop@2add963021 (2026-08-22). Data as JSON: /api/errors/5a976e33608cd9ec. Report an issue: GitHub.