Do not take this the wrong way but based on your question alone it shows you are doing something thats highly likely way over your head and technical knowledge currently. There really is any OS called "Linux" but there are tons of distributions out there with many of them being great down to poor unmaintained junk. When you pick a distro its usually based on your business needs and who has what skillset to manage servers either Windows or a Linux or Unix distro. A 1U rack server means almost nothing without saying the model and specs.. usually your application will determine what the server sizing/specs are to be but thats why I said this question really shows how badly you need to hit the books or training sites which we all had to do to get into this field.. when I came up it was read 7 1200page Microsoft Server cert books to get a MCP and MCITP:SA and then VMware came to life and I have been a VCP since they first had a test... This sounds like its for a business not a sandbox for you to play at home with right? Is this a micro small business that doesnt have any current IT infrastructure? If that is the case you can consider your timing to be lucky because we now have very mature, secure and mostly stable enterprise level clouds out there where if you are starting a business or your business is small and just now starting to "need" server based services like Active Directory

and other basic enterprise functions and with the right person or training you can basically now do anything in AWS or Azure and all you really need to do is make sure you have business class internet with enough bandwidth to support what the business is doing.. most businesses are going to have a mix of servers like Windows Server for their Active Directory Services, DNS, DHCP, Email and so on and many times the developers will need/want Red Hat Enterprise Linux or "RHEL" for short.. While you can get most any distro of linux free Red Hat is the industry leader in the game because they sell their enterprise level products with support agreements and you will need to do the research on those costs as it will help you understand vs a random person giving you information and I honestly couldnt tell you the last time I knew the price of a single cal for Windows because since 2016 I moved to a new business to manage their VMware on converged infrastructure (now hyperconverged or HCI) and we are over 99% virtual with

only a few standalone physicals for AD infrastructure and we have a few apps out of thousands that "need" to be physical mostly because they have hundreds of TBs or even a PB+ of data and they would constantly have issues and instead of fixing code they would blame it on being virtual and they complained enough to get executive override to go physical and I told them when they asked they would still have the same issues because they were already 1:1 on VMware as a "special case" and wouldnt you know they all still had the same issues until a years later when someone finally fixed some issues in their code. With 1 physical server what are you going to do when the motherboard fails

and if you didnt purchase 4 or 8hr support with parts for X years you could be down days, weeks I dont even know.. thats why cloud is the way to go for any new businesses or growing business and you will hear cloud is expensive but thats going to come from a lot of guys with my background we were built and formed by building servers on Dell, HP, Cisco etc and wiring up datacenters because thats what you had to do before cloud was actually useful, secure etc.. Does this businesses even have a firewall that is capable of protecting servers behind your connection? If not its just another reason to go cloud but that server might still be useful to have onsite.. If you go with Windows Active Directory it may make sense to have a local server onsite part of that domain for onsite users to have quicker logins and such but with todays speeds and with AWS having so many datacenters all over the US and world I dont even know if small businesses even go that route now or not.. I have been in this huge org now for 8 years where we have nearly 80k

servers (virtual) 30k containers all virtual on top of VMware and 25k+ virtual desktops with VMware Horizon and this is all in the most regulated field there.. think $$.. So with it being so big we have entire teams dedicated to everything.. like we have a "smallish" cloud footprint I am told with a few million per year in spend and I cant even tell you the name of anyone on that team we just have zero interaction and if this was a normal sized company say 1k-5k employees the IT team would likely been all together and maybe a 8 to 16 person sized team and maybe another 10 for helpdesk which was about the size of most places I had been before moving over to this gig.. you want to be in a smaller

sized place if you eagar to learn but this may be too small if you dont have anyone already skilled to learn from and honestly you will need to read or bust out the credit card and at least do free trials of Pluralsight and one other although i believe pluralsight has bought almost every competitor at this point. Hope that helps a little but just my 2 cents on the OS pick because of lack of time/knowledge etc for now Windows Server is probably your best bet especially if your decent with current Windows 10/11 desktop they

have basically made server look like windows 10/11 which is obviously a user friendly GUI.. Some linux distros come with a gui but most server builds will be command line based but a gui can be installed but legit linux admins would make fun of this lol... this is also another reason most people even doing just home lab setups to learn and get certifications they take a used 1u or even now with the smaller intel nucs and other mini platforms coming out with 32GB/64GB+ of ram and decent processors and vmware will run good on them so you dont have to choose a single OS but its hard to do alot of the training and learning with just one device which is why if you do some research on latest vmware homelabs you can get ideas of what others blog about building them and go from there... William Lam a vmware employee has an infamous blog where he writes alot about homelab stuff but just explore the tech bloggers and youtubers that alone will help you learn alot..