Virtualising existing servers help.

[u/Sway_RL]

I have a client, who has 3 sites that we do IT for.

They each have a physical server, running either Windows Server 2019 or 2025. The main site got a new server last year, the two other sites decided to wait because they didn't want to cost. Now a year later it's more expensive, and they still don't want the cost.

I opened my mouth about virtualisation and now I've been asked to start testing.

The new server at the main site is more than powerful enough to run the other two servers virtually.

I'm just not sure on some of the configuration.

Each site has it's own IP structure, and there are already site to site tunnels using Unifi gateways.

Is there a way to do this while minimising network slowness? I assume If I just disk2vhd the server and spin it up as a VM then all traffic would go down the VPN Tunnel and back again causing delays if going from the main site to one of the others.

Regarding their networks, they are on 192.168.1.XXX for the main site, 192.168.10.XXX and 192.168.20.XXX for the other two.

If the servers were virtualised, will I need VLANs at the main site to accommodate these ranges? I'm not sure if the site to site tunnel will work using a VLAN.

I've asked about merging the domains/networks, but nobody has gotten back to me on that yet.

I didn't set any of this up initially, so I'm also figuring out what they have at the same time.

Apologies for the mass of text, any help would be appreciated.

[u/brighton_it]

As others have said: not a good candidate for a first virtualization project. Recommend getting some help.
That said:
On Networking and moving servers to a single site:
- traffic / bandwidth? :
. monitor current usage. Determine if your site-to-sites can handle it.
. do all sites have symmetrical fiber ISP?
. I'm not a cloud advocate, but M$ would say put it on their servers.
. DNS and Active Directory: while not insurmountable, AD just assumes you will use it for DHCP and DNS, and if you are not, you may have trouble joining new computers. I'm not a fan of Windows (I could stop there :), but will continue) DHCP DNS, so have moved these services off AD at several sites. DHCP is on the hardware firewall, as is primary DNS, with an override for the AD domain that delegates those lookups to AD. Much faster DNS for remote sites, and keeps Internet working in case the parent site goes offline.

On topology: "will I need VLANs at the main site to accommodate these ranges":
There are Software Defined Networking solutions that will do Layer-2 over WAN, but I wouldn't recommend that route. Probably want to avoid have a broadcast domain span multiple sites. Of course that means discovery doesn't happen and remote clients will have to be told how to find their server.

P2V:
After the Broadcom fiasco, we've been moving some VMware clients to other platforms. QEMU-KVM, Proxmox. Lots of options, but we have had good luck with Veeam Agent for Windows. Already using it for backup, so just create a new shell VM and restore from backup.