UDF volumes have a single (hierarchical) directory structure to access files. Because of this hierarchical directory structure, the depth of a directory tree has a direct impact on file performance. For example, if /DIRECTORY1 contains 1000 files and /DIRECTORY2 contains 100 files, file search times for files in /DIRECTORY1, in general, take longer than file searches in /DIRECTORY2. This is because the system performs file searches hierarchically, which may require looking at every entry in the directory.
In general, file performance is better for UDF if you evenly distribute files across several directories and subdirectories.
