How to calculate the required characteristics of a virtual server?

Question

MySQL

You need to select the characteristics for hosting over 20 company sites and 1 CRM (not 1C, just an admin panel in a browser).
Sites are written in PHP, MySQL database.
The number of CRM users is about 30 people.
The total number of website visitors is more than 100,000 hosts/month.
We chose one Ukrainian hosting provider for VPS due to the ease of administration.
The question is how to choose the right package from those offered by the hoster, which differ in hardware characteristics. In which direction to dig, among the scattered information on the Internet, you can tell me the links or “by eye” poke ... I decided
on the volume occupied by the SSD, but I don’t suppose how to calculate the processor frequency and RAM.
Suggested options:
1) Proc: 1x2.6Ghz, RAM: 512 Mb
2) Proc: 2x2.6Ghz, RAM: 768 Mb
3) Proc: 2x2.6Ghz, RAM: 1024 Mb
4) Proc: 2x2.6Ghz, RAM: 2048 Mb
5) CPU: 4x2.6Ghz, RAM: 4096 MB

Answer 1

It is necessary to carry out load testing on hardware from the middle of this list, and depending on the results, choose it or another.
If you blindly choose, then I would take 3 for an unloaded site. Simply because it makes no sense to choose less than 1GB of RAM.

Answer 2

Try.
Servers can be very, very different, the load can be very, very different.
I personally and 50 servers live perfectly on a tariff plan of 200 rubles.
Nothing slows down.
And there is one server that eats 25,000 rubles a month....
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Look at the "recommended requirements" in the documentation for your CRM.
For it is she who will eat the most, I believe.
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This also depends on site attendance, but you didn’t tell us about attendance, and you yourself don’t know, apparently
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This is not a problem at all.
Take a hosting type VDS / VPS (it's inexpensive, from 150 rubles).
Not enough - increase the tariff plan.
Almost all hosters allow you to increase it upwards without any reconfiguration.
And sometimes even without a reboot.

Answer 3

do not suffer from garbage, if you don’t know how to prepare load testing, then take a small package and increase it as needed, it takes a minute to increase resources