apache/hadoop · error · IOException

failed to initialize lost+found

Error message

failed to initialize lost+found

What it means

Error "failed to initialize lost+found" thrown in apache/hadoop.

Source

Thrown at hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/NamenodeFsck.java:1001

    try {
      HdfsFileStatus hfs = namenode.getRpcServer().getFileInfo(path);
      return (hfs != null);
    } catch (FileNotFoundException e) {
      return false;
    }
  }

  private void copyBlocksToLostFound(String parent, HdfsFileStatus file,
        LocatedBlocks blocks) throws IOException {
    final DFSClient dfs = new DFSClient(DFSUtilClient.getNNAddress(conf), conf);
    final String fullName = file.getFullName(parent);
    OutputStream fos = null;
    try {
      if (!lfInited) {
        lostFoundInit(dfs);
      }
      if (!lfInitedOk) {
        throw new IOException("failed to initialize lost+found");
      }
      String target = lostFound + fullName;
      if (hdfsPathExists(target)) {
        LOG.warn("Fsck: can't copy the remains of " + fullName + " to " +
          "lost+found, because " + target + " already exists.");
        return;
      }
      if (!namenode.getRpcServer().mkdirs(
          target, file.getPermission(), true)) {
        throw new IOException("failed to create directory " + target);
      }
      // create chains
      int chain = 0;
      boolean copyError = false;
      for (LocatedBlock lBlk : blocks.getLocatedBlocks()) {
        LocatedBlock lblock = lBlk;
        DatanodeInfo[] locs = lblock.getLocations();
        if (locs == null || locs.length == 0) {

View on GitHub (pinned to 2add963021)

Solutions

1. Ensure the fsck user has permission to create /lost+found and that the NameNode is out of safemode, then re-run fsck with -move.

When it happens

Trigger: fsck cannot create or initialize the lost+found directory for corrupted files.

Common situations: Running 'hdfs fsck / -move' in safemode or with a user lacking write permission at root.

AI-assisted analysis of apache/hadoop@2add963021 (2026-08-22). Data as JSON: /api/errors/b9cd63331bd4bdb6. Report an issue: GitHub.