(Is the following an FAQ? If so, apologies, point me in the right direction...)
In years gone by, on a typical UNIX filesystem, creating entries (e.g. new files) in a directory could become badly inefficient as that directory size increased. By the time that (for instance) a "/var/spool/mail" reached (say) 20,000 entries, the acts of creating and deleting lockfiles in that directory could seriously impede things. (As a consequence, various sites devised various workaround; for instance we split into 100 subdirectories based on "uid mod 100", so that each subdir was only around (say) 200 entries.
When we migrated this to NetApp a couple of years back, we simply kept this subdivision in place. But now another consideration is coming into play which would be eased if we could consider reverting to the single large (~20,000 entry) directory.
Do such efficiency considerations matter in NetApp WAFL?