@Andrew_Murray
Hello Andrew
And Welcome to the NethServer forum!
I myself was a longtime SME-Server user, but due to issues with upgrading and hardly any development any more, moved on to NethServer.
ClearOS and Zental are more geared to $$$ interactions, less open source in my opinion.
NethServer can do RAID1, and RAID5 (SoftRaid).
Most here would suggest not to do a bare metal installation (In 2020, virtualization is king!), but use a Class I Hypervisor like Proxmox, VMWare, Xen or even Hyper-V.
This let’s the Hypervisor take care of RAID, but also Snapshots, Backup etc. Good peace of mind in case you installed something which didn’t work out, outages, defects or even Update issues! A quick Rollback, and you’re up and running again.
Personally, I use Proxmox to support my 25-30 clients using NethServer. It’s as free as NethServer, and has a lot of features like Linux Containers, Any OS Live Backup, Fast Migration, Cluster and more. Proxmox also supports out of the Box ZFS - easy to set up even as boot system!
The Docker Module is, AFAIK more for Devs or People who know what the want and can handle Docker. There is no Docker App-Store (yet) with polished Apps. Something like an App store may be coming up, there are quite a few plans / discussions going on, what NethServer 8 will bring!
NethServer comes with a very vibrant and supportive Forum, one of the best in Open Source I’ve found!
Don’t hesitate to ask any questions here!
My 2 cents
Andy