How is the file distributed on the server?

Question

Data storage

There are 3 drives on the server.
All 3 drives have a capacity of 10 GB.
1. 2 free
2. 5 free
3. 10 free

Questions
1 - a 5 GB file arrives, will it be written to all 3 drives in pieces or to a specific drive?
2 - which one? 2nd or 3rd?
3 - how is the order of drives determined?

4 - a 6 GB file arrives, if it is written all on the 3rd drive, then it turns out that all the rest will be idle if the files arrive from 6+ GB. So right?

The question arose while driving home, how the file bits are distributed on the server.
Let's say we have 25 SSD slots. Their volume is different, say, a multiple of % 2 = 0. And if all the files are from 3 GB, then 2 GB will be idle in each slot. That with 25 slots, this 50 GB will just hang. In practice, of course, in the case of a 1TB SSD or more, this is a trifle and will not be noticeable, 999 will be occupied and 1 GB will hang. When you have a data center with hundreds of servers and thousands of
drives, then these are already thousands of GB hanging in the air.

Answer 1

Where did this come from? You heard something for example about RAID? In the data center, where there are thousands of drives, they don’t use it all that way, there appears another layer for combining disks, where it doesn’t matter how the file will physically lie there.