Max Memory setting AWS EC2 we have move some SQL Server from Physical to AWS EC2 - my question is regarding Max Memory Setting fro SQL Server instance - I used to change the memory setting in Physical server giving some to OS and some to SQL Server but I am not sure for EC2 - do we have to use the same logic like 10-12% to OS and rest to SQL server in AWS Ec2  or we can keep it default .
If there is an OS you should leave some RAM for it.
EC2 is just a VM, so whatever you usually do for VM also applies for EC2.