The Splunk Validated Architectures manual should help. You may be interested in the M3/M13 or M4/M14 models. See https://docs.splunk.com/Documentation/SVA/current/Architectures/M4M14
Thank you for your response, We have achieved the final same city disaster recovery architecture by combining M3/M13 and UF clone dual writing!
Well, it's actually _not_ a disaster recovery. It's a HA solution with some assumed level of fault tolerance.
@jiaminyunThere is no such thing as "0 RPO" unless you do make some boundary conditions and prepare accordingly. A HA infrastructure like the one from SVAs can protect you in case of some disasters but will not protect you from other ones (like misconfiguration or deliberate data destroying). If you're OK with that - be my guest. Just be aware of it.
RTO actually depends on your equipment, storage and resources (including personnel) you can allocate to the recovery task.
If you mean sending to two output groups from a single forwarder - that works until one of them gets blocked. Then both stop. It's by design.