Separate statistics on sites from Domain Access
I haven't actually tested this but you could maybe use separate database tables with different prefixes for the tables that the statistics module provides (accesslog, node_counter).

So your tables might be something like:


site1_accesslog
site1_node_counter
site2_accesslog
site2_node_counter


The domain_prefix module handles that. This module was a sub-module included in the main domain access module for Drupal 6 but was separated in Drupal 7.

There is also an issue here which seems to indicate you can use a small snippet of code in a custom module for this instead of using this drupal.org module, which is seemingly not well supported currently.

Keep in mind this is a fairly advanced usage of Drupal so I advise caution and lots of testing. Having said that though the tables you want to split are low risk compared to say the node or users tables.