Hi
I’ve more or less replaced all VMWare ESXi at my clients with ProxMox.
My reasons:
- Extremly stable
- Online Snapshots / Backup out of the Box AND reliable restores, even Exchange, MS-SQL et Al.!
- Live Migration / High Availability / Clustering out of the Box
- No Windows box needed for Administration or clustering
- KVM and Linux Containers in one solution
- Best of breed solution, in my opinion
The pricing model for ProxMox is VERY simple, VMWare feels like ordering a simple coffee at Starbucks…
I love NethServer, but I like using Best of Breed for critical stuff. ProxMox is among the best in price / stability / usability / management - and all open source.
Say if the job was to create a Word or Excel Macro, I, as a open source advocate would use MS Office on the current version of Windows (10). I wouldn’t do the job with Office for Mac nor even consider Libreoffice. I would try to make the Macro as compatible as possible to LibreOffice or Office for Mac (Can that even run Macros?).
Then again, running Macros in office isn’t the best way to do ANY task!
NethServer is in my opinion the best all-round Linux Server for SME and Home environments.
It easily beats SME-Server, EisFair, ClearOS and plenty of others. It also easily beats MS Small Business Server, when that was still around. If there’s no other Hardware around, by all means, run your virtualisation n NethServer.
I personally prefer the other way around. Even in a single server environment, I’ll use a ProxMox base and install NethServer in there. That gives me even more rollback options if something doesn’t work out as expected - like the recent 7.4 update…
Another reason is the Samba / AD part of NethServer, which in itself uses containers, a form of virtualization / encapsulation. This introduces a second IP to the system, but it’s not just ANY IP, this is the master AD for SSO, logins, permissions… This poses no problems when run inside of ProxMox.
A typical NethServer at a SME client of mine comprises like 250-400 GB of Diskspace. With ProxMox as a base, I can make an online (or offline) save to a NAS in say 30-45 Minutes, depending on LAN and NAS. If something goes afoul, I can quickly restore just the NethServer or whatever.
Running virtualisation on NethServer would mean restoring the whole NethServer AND all running VMs if it’s to be done quickly. Takes more time, depending on the amount and content of your VMs. Also, the state of the other VMs would be rolled back unnecessarily, as they didn’t actually have a problem. NethServer doesn’t (yet) offer several backups or splitting of content.
Online backups of running VMs isn’t yet in NethServers feature list, meaning also a risk for your VMs, as the backup would restore the running states of the VMs - unless you had a hand done script shutting down your VMs before NethServer does it’s backup, and restarting things afterwards. Anything runnind a database )MS-SQL, Exchange, etc.) is likely to be corrupt afterwards or in a non-consistant state if not considered and planned for.
As Joseph said: Trust is good, checking is better: I always test my Backups - If it’s never restored anything, it’s not worth wasting my time! I also test backups repeatedly every 3-6 Months. I’ve restored a clients MS-SQL / Exchange Server running on Windows Server 2012 - saved while running live on ProxMox on HP Proliant Hardware - to a Mac-Mini, also configured with ProxMox, running in my home LAN. Now, the CPUs in those two Hardware differ greatly, as also the controller, network interfaces and several hardware stuff. As expected, the Windows box fired up, all licences and certification issues intact. KVM does not identify the real CPU to the VM, but provides a standard KVM CPU.
That knowledge is VERY relieving in a crisis situation… 
My 2 cents
Andy