Do you have any ideas to achieve 99.99% availability of SAP R/3 running on Windows SQL environment.
Any case study would really help.
I have gone throught the HA guide of SAP, but it doesn't help beyond a general information.
We've achieved it at some of our clients. Cluster the DB & CI and run online backups. Make sure you have lots of transaction log backups so that the trans log doesn't get full. Then you're pretty much sorted from the hardware / SQL side.
One thing to watch out for though - Support packages / SP-stacks. These need to be applied, particularly if you're running HR (else you don't have up to date tax laws in your system). Although you don't need to take the system down for them, it is advised to avoid having no or very few users logged on the system at the time off application.