Can I restore zwave devices from multiple C7 hubs currently in a Hub Mesh configuration to one C8 hub, or will I have to restore from one C7, and move the devices from the second C7 manually?
No.
Yes.
I am in the same situation as I have multiple hubs based on protocol (zigbee, zwave, lan). Personally I plan to migrate my Zwave hub to my C8 since I have many zwave devices that are a pain to get to, reset, and re-pair so its the path of least resistance for me. Plus Zigbee devices "fall in place" so I will "seed" my C8 hub with device records setting the Zigbee ID, etc so when I reset a zigbee device it will match against the record I previously created.
No, I don’t think so. I don’t believe you can migrate this way. from what I understand, when you migrate, it doesn’t move the devices to the new hub, it tells the new hub to take on the z-wave identity of the old hub. If you do this a 2nd time, you lose the devices you just migrated, and you lose the hub ID as it gets assigned another new ID.
Migrate once using the tool, then migrate the others manually.
I am curious, if you felt a need to have separate hubs, why would you move all the devices back to a single hub? The new hub isn’t more capable than the old ones. I recommend you migrate just one, and monitor performance. Then you can manually migrate over time while monitoring performance.
FWIW in my case they are (at least when I made the decision to split things up). I split my hubs back when the C3 couldn’t handle the load and bought additional C4s. Since then I swapped out the C4s with C7s but I am growing tired of managing 4 production hubs so will be going down the path of a 3 hub setup: Radio (Zigbee and Zwave on same hub vs separate today), LAN, and a coordinator. I was originally hoping to get to a 2 hub setup but in speaking with support there is concern of the C8 handling my 280 total devices all on one hub plus apps and mesh from LAN.
280 devices is a challenge if you have a lot going on at once. If you live in a large home and are there by yourself, how many doors, windows or motion sensors can you trigger in a minute??
Compare that to the smaller home with 6 people/pets causing several triggers a minute. I know in my home I'm averaging events about once per two seconds. Plenty of time usually, but around meal times we're getting some specific seconds where 3-4 events occur. Depending then on how many devices an Event actions, increases the potential for a noticeable delay.
Maybe two device hubs, since the Z-Radios are the constraining resource. Perhaps combine the LAN and Coordinator going forward? Your LAN speed is a hundred times faster and thus the I/O resource constraint is resolved more quickly and the hub can move on to another task.
I've got 3 Device hubs because I have decided to limit my hubs to 65 devices. Nothing measured about "65", it's just an arbitrary number I gave myself. It's large enough that I only need 2 device hubs, but have 3. For me, I prioritize responsiveness over burdensome hub management.