Limits of promo codes generation

I have two questions regarding the generation of promo codes:

1. Is there a limit on how many promo codes can be generated in backend?
2. Is there a limit on how many promo codes can be generated per store view?

I was able to generate 2 million promo codes, I am just wondering if for higher values Magento will also perform the operation well.

Thank you,

Carla