Hi rahul-yadav,
This is unfortunately not something that can be easily answered. You are correct that all of those things will affect the ASM resource usage (such as memory and CPU usage) but I don't believe there is a specific calculation to perform to determine what resources will be needed because it depends on the number of ASM policies that are applied to virtual servers, how the policies are configured, and how much traffic is being parsed by each policy. It also depends on which other modules you have provisioned on the device among other things. I can say that at the very least you should have 8 GB of memory provisioned if you are running v12 or later software. This is noted in the following article.
https://support.f5.com/csp/article/K40257355
"To avoid capacity issues in BIG-IP 12.x and later, you should provision the BIG-IP ASM module on systems with at least 8 GB or more of memory. The system permits provisioning both BIG-IP ASM and BIG-IP LTM as Nominal in an 8 GB Virtual Clustered Multiprocessing (vCMP) guest (dependent on configured BIG-IP ASM features). However, you should provision the BIG-IP ASM system as Dedicated to allocate the maximum available memory for the BIG-IP ASM system. For BIG-IP VE and vCMP guests, you should allocate 8 GB or more of memory to the BIG-IP instance before provisioning the BIG-IP ASM system."
With all of that said, my recommendation would be to reach out to your F5 Account/Sales team to discuss with them.
Cirrus
