Before releasing the final version of our highly awaited eXo Enterprise Content Management 2.0 we are doing many QA and stress tests including the volumetry.
The current tests are done with 12 millions which means 156 407 812 items in the JCR repository (metadatas, binaries and others).
Of course not all the documents are stored in a single folder but with such an amount we can get many documents in one. Hence a pagination mechanism is necessary, to only load a subset of the folder at a time. That is why we have enhanced our AJAX tree component to support pagination and have synchronized it with the list/thumbnails pagination.
The result is neat and the performance really rocks.
Here is a screenshot, remember it is a web application!