apache/hadoop · error · SnapshotException

Unable to rename because {} has snapshottable descendant dir

Error message

Unable to rename because {} has snapshottable descendant directories and {} is a descent of a snapshottable directory, and HDFS does not support nested snapshottable directory.

What it means

Error "Unable to rename because {} has snapshottable descendant directories and {} is a descent of a snapshottable directory, and HDFS does not support nested snapshottable directory." thrown in apache/hadoop.

Source

Thrown at hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/FSDirRenameOp.java:637

  private static void validateNestSnapshot(FSDirectory fsd, String srcPath,
      INodeDirectory dstParent, List<INodeDirectory> snapshottableDirs)
      throws SnapshotException {

    if (fsd.getFSNamesystem().getSnapshotManager().isAllowNestedSnapshots()) {
      return;
    }

    /*
     * snapshottableDirs is a list of snapshottable directory (child of rename
     * src) which do not have snapshots yet. If this list is not empty, that
     * means rename src has snapshottable descendant directories.
     */
    if (snapshottableDirs != null && snapshottableDirs.size() > 0) {
      if (fsd.getFSNamesystem().getSnapshotManager()
              .isDescendantOfSnapshotRoot(dstParent)) {
        String dstPath = dstParent.getFullPathName();
        throw new SnapshotException("Unable to rename because " + srcPath
                + " has snapshottable descendant directories and " + dstPath
                + " is a descent of a snapshottable directory, and HDFS does"
                + " not support nested snapshottable directory.");
      }
    }
  }

  private static class RenameOperation {
    private final FSDirectory fsd;
    private INodesInPath srcIIP;
    private final INodesInPath srcParentIIP;
    private INodesInPath dstIIP;
    private final INodesInPath dstParentIIP;
    private final INodeReference.WithCount withCount;
    private final int srcRefDstSnapshot;
    private final INodeDirectory srcParent;
    private final byte[] srcChildName;
    private final boolean isSrcInSnapshot;

View on GitHub (pinned to 2add963021)

Solutions

1. Avoid renaming across snapshottable directory boundaries that would create nested snapshottable directories.
2. Disallow snapshots on one of the directories (hdfs dfsadmin -disallowSnapshot) before renaming.

When it happens

Trigger: Renaming a directory that has snapshottable descendants into a location under another snapshottable directory, which would create nested snapshottable directories.

Common situations: See trigger scenarios.

AI-assisted analysis of apache/hadoop@2add963021 (2026-08-22). Data as JSON: /api/errors/1566acf7534b6343. Report an issue: GitHub.