I have a new C-7 coming. Currently use a C-4. I only have z-wave devices.
I want to use multiple hubs to achieve better stability overall. I would use Hub Mesh.
So I thought I would use the C-7 for all my devices and drivers only.
Then use the C-4 to keep RM, apps, virtual switches, dashboards and kiosk.
What are your thoughts to this strategy?
How large is your house? If a fairly good size you might consider splitting out by location - use the C-7 as the main hub and the C-4 as the "satellite".
My multi-hub config was 2 C-4s - one covering the basement and first floor the other the upstairs. Worked really well.
I would also consider keeping device rules local to the hubs they run on. That way if a hub goes down it won't impact (as much) the other. You still get the benefit of lower resource utilization because you are splitting up devices and rules that would normally be on one hub. Also if you need to migrate less devices per hub to futz with.
Another strategy (and I am full of them today apparently) would be to use the C-7 as the main hub with all devices, re-purpose the C-4 to be cloud and network devices.
If you really wanted to go crazy you could follow some of us down the Node-RED rabbit hole.. then you could eliminate most of the HE system apps except for a few critical ones.
My current multi-hub setup is a C-7 for Z-wave, a C-5 for Zigbee and a C-4 for cloud (Alexa)/network (lutron etc) devices. Rules and integration provided by Node-RED running on an RPi (along with HomeBridge!!!).
My house is 3 story, all brick and cement walls/floors.
What about the apps? Should they be split as well?
I have an enclosed server room on the ground floor with ALL my networking, AV, security, etc inside. How is the C-7 radio? Is it really better than the C-4 so I should still get good reception?
All my networking is hard wired, homerun to the server room. Including all sensors. Only the Z-wave would be wireless of course.
Following for ideas. I just got a C7 to replace my C4, but now am seeing what I can still use it for.
I don't really know if the radio is actually better in practice just yet but the claim is that it is.
I mentioned in a previous thread - I have a client with a 3600 sqft older house with 3 floors and a basement. The C-7 hub is in a central place on the main floor. I am able to get Z-Wave all throughout the house thanks to some repeaters and powered devices. I did have to add a C-5 hub to the detached garage though due to signal issues.
In your case I think you could get away with the C-7 for all local devices and use the C-4 for cloud/network device stuff. I would consider Node-RED if you want to lower hub resource usage further.
edit: the reason to move cloud stuff to the C-4 is to prevent slowdowns / erratic behavior if internet drops.
The C7 has newer zwave stack / radio chips. It is not clear in your environment that you need that now if you zwave mesh is otherwise healthy.
As to memory / cpu, they are near enough the same.
It is a fair amount of work to move all the devices to a new hub. My suggestion would be choose when to move based on you have an issue, vs. just doing a lot of work with potentially no change at the end.
So what are you fixing? and if it ain't broke, don't fix it.
What? You need to turn in your geek card!!! You ALWAYS have to upgrade right??
There are at least two maybe not so critical reasons (?excuses? 
) to move away from the C-4 as a primary hub:
To be fair in practice that last reason probably does not matter for most setups though dunno. Depends on how many apps, rules and devices you accumulate I guess.
I have 37 devices. I do experience stability issues with the C-4. Support tells me it is from an app, but I do not know which one yet. I have been away from home almost a year now (covid) and several devices are not working. My hub needs rebooting about once a week which I can do remotely (hard boot only). So this at least keeps it limping along.
I bought a C-7 to take back to my home which is the reason for this post. I want to pre-plan best use once I get home.
I think that splitting the loads between the hubs would help with stability, PLUS running down this troublesome app would go a long way to get my HA running solid.
I have a lot going on in my home with whole house A/V, networked security and 7 cams, weather station, access control, A/V control panels in 4 bedrooms, presence sensors, networked home theater, 2 kiosks.
I run 3 go fast wifi routers (hardwired).
PC server runs 24/7 for Blue Iris dvr functions.
Download the Hubitat app
