Big installations?

I'm wondering what the limitations are for an Omeka installation. How many items do you have in your sites? I'm evaluating if it might be suitable for 500000+ items? Does anyone have experiences of large collections of items?

The largest installation I know if is Florida Memory, which I think has at least a million items.

The capacity of course will depend on server setup and settings -- I'm not sure I'd try 1M on shared commodity hosting! -- but it should work okay. Configuring to use AWS is also an option.