问题
If I use Transparent Data Encryption on my database, is there any impact on my db performance? Is it cause any problem for database indexing?
回答1:
Some folks have tested this (see here, here, here and here) and have given some generic advice (see here and here). Seems the common perception is that the impact is about 3-5%. But 3-5% of what? If that is CPU and your workload is already CPU-bound, is that acceptable? Could it be worse? If that is I/O and you're already having I/O issues, is it going to kill your system? Who knows?
The best way you're going to determine what impact it will have on your performance is to test it in your environment. There are so many "it depends" factors here it's not funny. You should test your workload, against your database, on your hardware, over your network, with your usage patterns and backup procedures. You may have people coming back and saying "it hurt my performance a lot" or "I didn't even notice it" but how similar do you think their scenario is to yours?
回答2:
Aron is absolutely right. What will be surely affected is size of all your backups. You have to think about backup compression as it doesn't exist when you use TDE. And it means all backups & log shipping will have much worse performance.
来源：https://stackoverflow.com/questions/9250175/what-are-impacts-of-tde-enabling-on-database-performance