Best method for creating multiple content sources for single web application in sharepoint 2010

Hi,

I have a web application (Intranet) which contains around 9000 site collections. Currently I have created single content source to crawl the entire web application, but it is taking more than 200 hours to complete the full crawl and also subsequent incremental crawl duration is high. This is causing the performance in the search & user needs to wait for a long time for crawling new items.

I am planning to create multiple content sources for this web application & the start address would be till managed path( http://<intranetsite>/<managedpath>/).

Please suggest if I can achieve this plan & does it make any performance issue in crawler & DB side. Also suggest if there is any alternate method to split the site collection to 2 or 3 content sources.

Thanks in advance.

Regards,
Anoop