I now have 2 x C8s--only one is active. What are the possible use cases for running 2 simultaneously? Eliminating a WiFi switch that controls cold boots for my active C8 is an obvious, albeit extreme, one. I'd love to hear your collective thoughts as to others?
Thx!
Seperate z meshes
Geography coordinated
Local vs cloud segregation
Development
A guinea pig hub to abuse.
Just my initial thoughts. Likely not all imclusive.
Many similar threads you could dive into for more ideas.
There are a lot of reasons for running multiple hubs. I have a C-5 to isolate all of my Sylvania zigbee lights (and anything else that I deem unfit to repeat for Zigbee locks and sensors) to their own mesh (about 40 Zigbee devices). My C-8 has all of my Z-wave devices, all zigbee battery devices (including 4 locks), and the Zigbee repeaters that have proven themselves reliable (103 zigbee devices). My third hub is a C-5 that I migrated to my C-8. It now runs Echo Speaks, Home Assistant Device Bridge, and other cloud integrations that use a lot of resources. It’s also where I try out new things before using them with my main hubs. They are all connected by Hub Mesh.
Thanks, I read many other threads (including non Hubitat ones). Many suggested reasons, few delved into why. I'm looking for reasoning as well as reason.
Why would I?
I get it but, again, why? Processing load?
Agreed, this is a great reason and is my current plan.
Perhaps, but it's an appliance for my home (not my dev laptop)--I need to abuse the one I use to determine interaction and broader effects. Repeatedly cloning one to the other doesn't work so not seeing the value in this one.
FWIW, I have 2 C8s, 1 C5, and a C7 in "production" and a spare C7 (just in case) 
Hub 1 retired in good graces. A C4.
Hub 2 C5 #1 runs Rule Machine rules, Room Lighting rules, CoCoHue, and the Sonos integration, plus a few other small apps.
Hub 3 C8 #1 handles Zwave and Zigbee in my utility area and part of the basement where HVAC ducts, appliances and piping make for poor signal propagation outside of its close proximity.
Hub 4 C8 #2 runs my main Zigbee and Zwave+ meshes, and is the source of the bulk of my hub mesh devices. It runs just a couple RM rules, and my Zooz Garage Door opener app as well.
Hub 5 C7 #1 currently only runs some custom code to average Luminance, Humidity & Temperature that I adapted from some of @bravenel's posted snippets. It will probably take over some of the LAN based integrations at some point, like CoCoHue, Ubiquiti & Sonos.
I may ultimately decentralize the RM/RL funtionality too, but we'll see.
S
Thanks!
I guess I need to simply try it to properly grok how Hub Mesh works. 
Are you saying that your C5 serves as the runtime for the Echo Speaks middleware (last I read, this required a Pie or the like)?
Whoa!
Thanks for the detailed response!
Why do you feel it necessary to decentralize to this extent? Is a single C8 not capable of running all of this?
Just the ES app, which is fairly resource heavy. I have a pc running Ubuntu for the ES cookie server, HA, pihole, and an ntp server.
Sometimes a second mesh is nice for increasing the available bandwidth, especially for people with a lot of z-wave devices.
Some people seem to think it’s necessary. I have never had an issue running one C3, then one C5, then one C7. I haven’t upgraded to a C8 yet but I don’t expect to use more than one.
I don’t have the largest z-wave or zigbee meshes, but they’re not tiny. And I don’t run every possible LAN or cloud-based integration though I do have at least a few that are considered resource hogs like Echo Speaks.
So far so good 
.
Got it.
In your experience, what qualifies as a lot of Z-Wave devices for a C8--I'm at ~60 and it's growing rapidly. Sq footage hasn't posed a problem thus far once the necessary repeating devices are in-place and bandwidth hasn't proven an issue either (makes sense given the packet size required to turn a switch on/off/dim/etc.)
Thx!
Out of interest, how many devices do you have?
Well. My wife would probably say its an illness, but...well. ummm.
Really 1 C8 would be sufficient. I like the separation of rules from radios just because I started with a single C4 and my mesh size and rules seemed to strain the hub a bit. At least subjectively. When Hub Mesh was introduced, i found it answered the mail for me.
Now...welll, the C7s were bought to replace the C4/C5 pair, and well...i just never got around to moving all the rules from the C5 to the C7s. And then, well. The c8s came out. Shiny. And here we are.
I think if i were to redistribute everything from scratch, i'd probably distribute some rules and devices across several hubs, but having said that I like the way stuff is distrbuted generally....so maybe not.
I have 49 Zwave, and 70 Zigbee on Hub 4, plus Sonos (10) Hue ~25, and a stupid amount of Ubiquiti devices.
There's another 15 Zwave on Hub3 and 7 Zigbee.
S.
And...well. there might be more devices....there are always boxes arriving!
That’s usually a good place to stop from what others, including Bruce, have posted. Problems with bandwidth start showing up eventually. I have mostly Zigbee devices and only 30 Z-wave.
LOL, love it! Same in many respects outside of the # of hubs but certainly on the wife's commentary.
It's becoming more apparent that I simply have to try the mesh since I'm naive to how seamless it is. From what I can infer, I'd at least have to check the 'hub mesh enabled' checkbox for every device that made sense to share. I think it's this that perplexes me--what's the strategy in this regard? Share 'em all; share some... if so, which; etc.? Any insights appreciated. 
Interesting. Now that you mention this i may recall some of these conversations. I've been having really odd Zigbee issues lately, that ive been struggling to nail down. I may have to rehome some Zigbee devices for better bandwidth management... thanks for posting this!
S
Thx.
I'm beginning to think I took the wrong path between Z-Wave and Zigbee (Matter/Thread/WiFi wasn't in the running at the time). Zigbee appears to be simpler overall--is that your experience?
Interestingly, Ive been considering this myself.
In the early days of my use of the mesh, I tended towards "install & share everything". With this approach, the rules hub can see all, and rule all.
However. Presently, I'm tending to minimize sharing to just the devices I need for a specific rule, and if they aren't in a rule or dashboard they aren't shared. I think this is a bit easier to manage, and reduces some resource utilization by the mesh source hub and rules hubs both.
In other words, consider the rule, share the devices, build the rule.
S.
Yes, but it’s definitely dependent on buying reliable devices. There are a whole lot of cheap Zigbee devices out there that don’t follow the spec.
There is no wrong or right here. Zigbee "seems" easier and has advantages in some situations, but Zwave+ is great too, and has a better selection of devices for dimmers, switches, and in some cases sensors. Both are useful, reliable and valid.
Matter & Thread remain mostly marketing hype, and Wifi ...well. it has its place, but...that way lies chaos.
. I totally agree btw
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