Recommended HA latency for ISE between countries

[AndrewWai]

I am planning an intercontinental High Availability (HA) setup with the primary ISM VM located in Singapore and the secondary in Mexico, covering both Asia and Western regions. In this context, I would appreciate your guidance on the following points:

1. Recommended Latency: What is the recommended latency for HA operations between these two regions?
2. Pros and Cons: Could you detail the potential advantages and challenges of this HA configuration?
3. Best Practices: Are there specific best practices or tips that should be considered when implementing this setup?
4. Issue Anticipation: What unexpected issues might arise from such a configuration, and how can we proactively address them?

Thank you for your assistance in ensuring a robust and efficient setup.

[marce1000 · Accepted solution]

 - Ref :  https://www.ciscolive.com/c/dam/r/ciscolive/us/docs/2020/pdf/DGTL-BRKSEC-3432-reference.pdf
                      And or start reading from What if Distributed PSNs > 300ms RTT Latency? 

 M.

[ahollifield]

300ms between the ISE nodes.  How stable is the WAN, potential for split brain?  Is this a small two node deployment?  I would consider three node deployment at the minimum.  

[AndrewWai]

1x PAN, 1x MnT, 2x PSN (Dot1x & TACACS) for primary and same as secondary

[ahollifield]

This is not a supported deployment type.
https://www.cisco.com/c/en/us/td/docs/security/ise/performance_and_scalability/b_ise_perf_and_scale.html