Zero downtime deployments

Hi all

I have been discusing a zero downtime approach for a standard Episerver CMS 9 site (no Commerce or Find and doesn't use Forms). The approach will be using traditional infrastructure on VMs so I'm afraid using Azure deployment slots isn't an option right now :)

Current thoughts revolve around two load balanced servers (A) and (B) using a shared database. The approach is as follows:

1. Put Episerver into readonly mode 
2. Take server (A) out of load balancing pool
3. Replicate DB
4. Point server (B) to replicated DB
5. Apply changes (code and DB) to server (A)
6. Smoke test server (A)
7. Bring server (A) back online
8. Take server (B) out of load balancing pool
9. Apply changes to server (B)
10. Bring server (B) back into load balancing pool

Does anyone have any thoughts inisights/they can share on this? Have you done this yourself?

Appreciate your thoughts!

David