I just got a C-8 Pro for Xmas to replace my C-5. I was trying to decide what to do with the C-5. I think I'm gonna take the following approach:
C-8 handles the devices. All Zigbee, z-wave, matter, and Ethernet connected devices will be primarily attached to the C-8, and shared with the C-5 via Hub Mesh. The C-8 will only handle essential device actions, like "press this button, turn on this light", etc.
The C-5 will have control of devices via Hub Mesh, and will handle all automations, modes, scenes, dashboards, etc.
The idea being I have one main controller dedicated to handling all the directly attached devices. This device should be stable and almost never gets rebooted or touched, and just runs in the background providing access to all devices. The other Hubitat will essentially do all the work of automations and dashboards, and this way if a badly written automation or beta platform update or whatever breaks the C-5, I may lose automation but I still have normal control of all the house devices and lighting.
Does this seem like a logical way to utilize two Hubitats in one location?
Fairly similar to what I do with 2 C7s, and 1 C8. -
The prod C7 handles Zigbee (mainly battery sensors) and network, cloud, and high level rules (modes), dashboards, health checks (temp controls, morning battery checks, yolink+ecobee integrations), timed events (morning wakeup, good night shutdowns, etc)
The prod C8 is all ZWave, Matter, and "urgent/fast" rules (water leaks, lights tied to motion/contact sensors). The 800 series radio and external antennas seem to help here.
Last C7 is development/testing only, groovy code, strange device testing, beta firmware, etc.
All interconnected as needed with Hub-Mesh. Breaking up the C7 and C8 helped alot, and our only real differences is that I kept Zigbee on the C7, as the C8 seemed to initially have many Zigbee 3.0 issues.
So yeah, I think your headed down a reasonable path, the only other consideration would be to use your C5 for dev/testing, if you want a more formal release approach (and higher WAF)
I have a unique use. I replaced my C7 with a C8 Pro. I now use the C7 dedicated to only the HD+ app for score-keeping a card game that we play often (Hand And Foot). I have a large Samsung monitor connected to a Rpi running a large HD+ dashboard. The HD+ app displays all of the card game information. I use a sister dashboard on my phone with webcore pistons to do the calculations for game-play/scores.
0 = all Lutron devices, and their rules
1 = all Zigbee/Z-Wave devices, and their rules
2 = all time-based rules (including mode switching), presence, Sonos, and system-wide flags (AWAY, VACATION, HOLIDAY, etc.)
Hub Mesh between hubs where necessary (Picos controlling Zigbee outlets, etc.)
Previous generations (C5s and C7s) are boxed in the basement, waiting for new homes when friends get curious.
I have been a multi hub user for 6 years when I learned my C3 couldn’t handle all my devices and apps. I ran 4 hubs for many years where I had a coordinator, zigbee, Zwave, and lan hub. Once the C8 Pro came out I now only run 2 hubs where one is radio only no apps, and coordinator hub that runs apps and LAN.
I would honestly suggest you use your new C8 Pro as your app hub and keep your C5 for devices. Unless of course you need the new radio chips. I suggest this because apps and hub mesh consume a lot of CPU and memory. My old C7 coordinator always had the lowest memory, high CPU and database. Also required more frequent reboots.
C8 and C7. Almost everything runs on the C8. A mix of ZigBee, z-wave some local WiFi, Lutron Pro and Hue hub. 280 some real and virtual devices. The meshed C7 for development and handles an instance of Ecobee Suite so I can get the actual Ecobee thermostat temp and a ZigBee mesh interrupting Osram light strip. The C8 has a hub protect subscription so the radios can be restored if it fails. I doubt I have the patience to pretty much start from scratch if I had to reconnect all of my devices. At this point the C8 is good for about 2 weeks between auto reboots based on free memory.
I use one hub for running network, cloud, and virtual devices such as Aqara, echo, OwnTracks, and Tasker devices as well as the dashboard (no zigbee or zwave devices).
These devices are connected via the hub mesh to the other hubs.
General speaker notifications also run on this hub.
My other four hubs are divided up between different areas of the house.
The devices and rules for those areas run on that areas hub.
This way if any 1 hub fails it only affects the one area and is easier to trouble shoot.
All hubs are networked together through the mesh as some rules do require devices from different areas and echo speakers from the cloud/network hub.
My primary HE (8) is handeling all zigbee, z-wave and matter communications.
The secondary HE (7) is only connected with matter to al my HUE bridges. This one also has the same lighting rules as my primary hub, with the expetion that those rules only are allowed to run if the primary HE is unavalible.
My C8 Pro has all the zigbee devices (and a couple close by zwave) and all of the rules. My C8 has all of the zwave devices, hub mesh to make the zwave devices visible to the C8 Pro. System works well.
I have a Ring range extender mostly to detect power outages which both hubs on UPS's will respond to after a brief period and shutdown. Those rules will abort shutdown if power returns before shutdown.
