seaweedfs/seaweedfs · error · UnsupportedOperationException

{getSimpleName} doesn't support createSnapshot

Error message

{getSimpleName} doesn't support createSnapshot

What it means

UnsupportedOperationException('<class> doesn't support createSnapshot') thrown unconditionally by SeaweedFileSystem.createSnapshot() (seaweed.hdfs.SeaweedFileSystem:393). The HDFS snapshot API (point-in-time, read-only copy of a directory subtree) is not implemented by this client, so creating a snapshot on a seaweedfs:// path always fails deterministically.

Source

Thrown at other/java/hdfs3/src/main/java/seaweed/hdfs/SeaweedFileSystem.java:393

    }

    public boolean supportsSymlinks() {
        return false;
    }

    /**
     * Create a snapshot.
     *
     * @param path         The directory where snapshots will be taken.
     * @param snapshotName The name of the snapshot
     * @return the snapshot path.
     * @throws IOException                   IO failure
     * @throws UnsupportedOperationException if the operation is unsupported
     */
    @Override
    public Path createSnapshot(Path path, String snapshotName)
            throws IOException {
        throw new UnsupportedOperationException(getClass().getSimpleName()
                + " doesn't support createSnapshot");
    }

    /**
     * Rename a snapshot.
     *
     * @param path            The directory path where the snapshot was taken
     * @param snapshotOldName Old name of the snapshot
     * @param snapshotNewName New name of the snapshot
     * @throws IOException                   IO failure
     * @throws UnsupportedOperationException if the operation is unsupported
     *                                       (default outcome).
     */
    @Override
    public void renameSnapshot(Path path, String snapshotOldName,
            String snapshotNewName) throws IOException {
        throw new UnsupportedOperationException(getClass().getSimpleName()
                + " doesn't support renameSnapshot");

View on GitHub (pinned to 1c926e8fac)

Solutions

  1. Use SeaweedFS-native protection instead: filer-level replication to another cluster, volume snapshots, or S3-style versioning depending on deployment.
  2. Implement an application-level 'snapshot' by recursively copying the subtree to a backup path before mutating it.
  3. Remove/disable snapshot steps in runbooks when the target is seaweedfs://.

Example fix

// before
fs.createSnapshot(dirPath, "pre-migration"); // UnsupportedOperationException

// after — explicit copy snapshot
Path snap = new Path(dirPath.getParent(), dirPath.getName() + ".snap-" + System.currentTimeMillis());
org.apache.hadoop.fs.FileUtil.copy(fs, dirPath, fs, snap, false, true, fs.getConf());
Defensive patterns

Strategy: try-catch

Validate before calling

boolean supportsSnapshots(FileSystem fs) {
    return !(fs instanceof seaweed.hdfs.SeaweedFileSystem)
        && !"seaweedfs".equals(fs.getUri().getScheme());
}

Type guard

boolean canSnapshot = !(fs instanceof seaweed.hdfs.SeaweedFileSystem);

Try / catch

try {
    fs.createSnapshot(dir, name);
} catch (UnsupportedOperationException e) {
    // fall back to a copy-based snapshot
    org.apache.hadoop.fs.FileUtil.copy(fs, dir, fs, snapPath, false, true, fs.getConf());
}

Prevention

When it happens

Trigger: Calling fs.createSnapshot(path, snapshotName) on a SeaweedFileSystem; scripts using 'hdfs dfsapi'-style snapshot commands; backup/DR tooling that snapshots directories before destructive operations.

Common situations: Disaster-recovery automation written against HDFS being repointed at SeaweedFS; admin runbooks that snapshot before big migrations; version-driven re-exposure when ops tooling adds snapshot safety checks.

Related errors

AI-assisted analysis of seaweedfs/seaweedfs@1c926e8fac (2026-08-15). Data as JSON: /api/errors/466a92ef8c7b26c7. Report an issue: GitHub.