If we connect warmspare across data centers will they still work. Each in a different center? Our datacenter distance is 25 kms. Are there any requirements to fulfill this connectivity with warmspare?
It’s not something I’d want to be trying. The warm spare is intended to be relatively close with low latency. You’d be better off looking to see if you can implement a data centre failover solution, see here https://documentation.meraki.com/MX/Deployment_Guides/Datacenter_Redundancy_(DC-DC_Failover)_Deploym...
This may look like a simple question but in fact I guess it's not that simple.
I'm not aware of latency requirements for warm spare pairs for example. Are you using dark fibre between these DCs? What is typical latency? Are you suing them as Active/Active DCs?
Normal latency between datacenters would be 3ms and max upto 10ms. No we are not using dark fibre between the data centers. We are using them as Active/Standby DC in this case.
Another question would be, during the Firmware upgrade how does the upgrade happen. What would be the difference between DC-DC connectivity and MX warmspare?
You require full layer 2 extension between the datacentres. So that every interface on the MX on both sites are connected at layer 2 (both WAN and LAN).
If this is being used for AutoVPN you could also consider running active/active. To do this each MX must be connected via a stub network to the main DC networks at each site.