Is there any benefit of using multiple lists to store documents versus a single library in large lists?

Question

Background: We are migrating a legacy system into Sharepoint and will look to migrate around 300 000 documents. There is some metadata which inherently diferentiates the documents from eachother.

Currently I have chosen to have 5 subsites with a doc library in each to essentially split the documents up roughly based on the metadata, however they all use the same content type.

I have written a custom interface for querying the data without the use of the default list views by using SPSiteDataQuery. My queries will always return < 5000 items as a lot of the number of documents in the list are actually versioned so throttling should not be an issue.

Question: Is there any point splitting up the doc libraries? Is there an issue with putting all the docs in a single list with regards to performance?

I'd rather have them in a single list and use SPQuery. It would also make other operations I need to perform easier to implement without having the libraries in different places.

Sharepoint can apparently store up to 30 million items in a list. Am I worrying needlessly about 300 000 docs in a single list? We are NOT using any folders or item level permissioning either

Answer 1

I don't think there is any point in splitting up the libraries given your use case if they all share the same content type and metadata.

But how big are these files? Are you taking into account SharePoint's maximum recommended content database size of 200GB?