Hello, this is my first post. 
I know Ignition can be installed almost on any PC, and OS. But, when your project is bigger you will need a better hardware.
For a project with more than 10000 tags and 5000 history tags, do is better install the server software on a Windows Server 2016 or installing over a win10pro is the same? 
For sql version, do is better use a sql profesional vs sql express? For example to store this 5000 tags every 1s.
Thanks very much, 
I’m of the opinion that in a production environment it’s better to use one of the Windows Server editions as it is specifically designed for server applications. You might be able to do it with windows 10 with but Windows 10 was designed for desktop applications, there’s going to be software on there taking up resources that you just don’t need on a server.
On the SQL side if you’re going to use Microsoft, then go for the full version of SQL. SQL express has a database size limit of 10 GB (for SQL express 2008 R2 and SQL express 2012), plus it can only use 1 GB of RAM, and 1 CPU (in SQL express 2012 this became the lesser of one socket or four cores to allow for multi-threading).
So technically, you could get away with SQL express, after all you won’t (shouldn’t) be writing all 5K tags every second. You should have some dead band values configured to minimize database writes so your database does swell out of size because a process value changed from 4.55556 to 4.55558. But that 10 GB database size will get you in the end, and a limit of 1 GB of RAM is pretty tight. Better to go with the full version of SQL.
It might also be worth checking out MySQL if cost is a limiting factor. If cost is really a limiting factor you might want to check out installing Ignition on Linux, a headless (no graphical interface, just command prompt) linux installation on a high end desktop PC is a very powerful combination for low budget environments. You’d obviously want to do some testing before recommending this to a client, but something worth considering if you know some basic Linux and MySQL.
Ariel,
You should be looking at the hardware and the networking options, not just the OS and the database software. Regardless of the OS and the database you run, if your hardware resources are lacking, you will have issues. For a modest system a good modern PC will work (a modern multi-core processor, a good amount of RAM, high speed spinny disk or an SSD, etc), and server-grade hardware or OS may not be required. That said, you will typically get better performance with server-grade hardware and a server-grade OS.
Another question is whether or not you are planning to run the database on the same machine as the Ignition Gateway. If you are, you will win on data transfer speed but may pay for it in performance if your hardware or the configuration are lacking. This is especially if you choose MS SQL Server as your database, which is a powerful and well documented database but a very memory hungry one and easy to misconfigure.
All things considered, Linux servers are the most robust option, but (1) you cannot run Microsoft software on them, and (2) it helps to have some prior experience with that OS.
As far as the choice of database, go for the one you or your customer are more familiar with, but stay away from SQL Server Express unless you are ok with it accepting only one connection at any time, and are willing to keep a close eye on the amount of data logged and clear old data regularly.