Many IFS files in directory

I was just thinking today about a project that I am working on that is
cataloging 22,000 PDF invoices (per day) on a Windows machine and the
approach we have taken to ensure top performance is to put no more than 1000
files in each directory by dynamically creating new directories multiple
levels deep instead of putting all files in one directory.

I thought this was just a Windows problem but then a co-worker of mine said
Linux had the same problem (or similar at least), and that got me thinking
about all of the files I write out to the IFS with RPG.

Does anybody know if the IFS base file system suffers from the same dilemma?

Thanks,
Aaron Bartell