SQL Server Backup Encryption on AAG
Yes, use the same cert on each instance. Your restore process would be clumsy if you had different certs on different instances.

I would suggest you read the documentation (including the relevant links) as encryption and key hierarchy in SQL Server is a topic too large for a single answer on a Q&amp;A site, but essentially you need to:


Create a database master key
Create a certificate
Backup your certificate and keys
Import the certificate to each node of the AG and any other instance you plan on restoring to
Use the ENCRYPTION option in your backup statements