I just got a C-8 and now need to migrate from my C-5. I've had a C-5 for a long time, and have had various issues, ghost devices, etc. Is it better to just start clean and remove each device from the C-5 and then add to the C-8? I know this will take longer, but does it eliminate any risk of carrying over issues from the C-5?
How do you know you have ghosts? (This is hard to see with a C-5.) But if you've addressed the problem, it should be OK.
In general, however, if you're having problems and migrate to a new hub, the problems will just follow you. If it's not too much effort and you can't fix whatever problems remain first (or if you think it's easier not to), starting over -- with some care (e.g., any secure devices that only support S0 and don't offer non-secure pairing?) -- may be best.
As above, probably--not like anything from the old hub configuration is around to haunt your new one--but it's important to identify the cause of the problem in the first place. For example, if you have a bad device or are dealing with range issues, starting over, whether a new hub or not, won't change that (except actually better antennas and newer Z-Wave on the C-8 might help, but I wouldn't count on this on its own)
If you aren't sure, sharing more details about your current situation may help others help you figure things out.
If you don't want to do a full migration, there is a different but tougher option. You could restore a C5 backup to your C8. That would bring in your automations, dashboards, driver/app code, and so on. It does not bring in the Z-wave radio database doing a local restore.
Zigbee devices would simply need to be put into pairing mode, and they would fall right back into place.
For Z-wave, you would have to rename the old DNI on all (Z-wave) devices. Then you reset and re-include the Z-wave devices. (ensure you don't create a ghost at each inclusion) From there, you do a swap device using the built-in swap app. This post has more detail as to what needs to be done if you use this method... Migrating a Z-Wave Network
I did this method when I migrated from C5 to C7, and while it was time consuming, it was worth it in my opinion so I could start over with a healthy mesh building the right way instead of haphazardly like I did the first time.
It was Hubitat support that identified ghost devices for me a long, long time ago. The only issues I presently have is that occasionally some of my motion lighting (zigbee motion sensors and zwavec switches) just randomly take forever or don't even respond. I got a C-8 hoping that I can better place my hub in the middle of the house using wifi rather than ethernet and between that and the better radios, those issues will go away. So maybe I'll just migrate it the easy way and cross my fingers!
Well if the ghosts transfer, they'll be easier to get rid of with a C8 as you will see them.
I'm in this same boat.
Very happy with my C-5, and have an unused C7 and unused C8 sitting around. Been meaning to do a migration to the C8... but not sure about the best approach.
Also wondering if I break out my C7 to be dedicated to apps while the C8 does the radio/device magic or separate by Zigbee/Zwave???
So many options!