Performance check of my database

Hi,

 

Lately I completed the business logic of my application and all related database work.

 

Now i need to check the performance of my database, how much load it can bear, perfomance to different queries and stored procedures.

 

Basically i need to do the performance testing of my database and based on that I need to take a call whether i should go for clustering or not.

 

Please let me know the best practices in postgres for such an activity.

 

Thanks ,

~Harpreet