how many max docs recommended in Windchill folder?

In the Windchill views, you can adjust the number of shown documents on each page. I have mine set to display 4000 items. I do have a few folders that have over 8K items, so I have to page through. Typically you will be doing searches, so the display list will be more refined than just looking in a folder. I do understand that as a system admin you do need to look in folders at times.

From a system OS level, I have my disk folders set to roll over to a new folder when they reach 50K files.

Windchill 11.0 m030

Windows Server 2008r2

Oracle DB

I have been using 10k objects per folder for the last 10 years with no issues.

Windchill 10.2 M030

Windows Enterprise Server 2008 R2

Oracle DB

When we were going to Windchill from Intralink at the end of 2011, I was given the rule by my VAR to stay under 5,000 objects in any directory.  I do not know if that still applies or not, but it makes some sense from a performance standpoint where the more you have, the worse the performance during browse.

We also capped off our file vaults at 50,000 files, but for some strange reason it likes to double that amount and I usually see 90-100k files there.