Resolution

As a workaround, change directories to a path that is not on an Xsan volume (such as the root directory) before running snfsdefrag, and avoid using snfsdefrag's recursive option (-r).

If you need to recursively defragment files in a directory on an Xsan volume, you can do so by running snfsdefrag from the find utility. For example:

cd /
sudo find /Volumes/MyVolume/some_directory -type f -exec snfsdefrag '{}' \;

Alternatively, you can use snfsdefrag normally as the file's owner.