> Moodle (the system itself) moodledata (Data/files stored on the system) and tmp (temorary files) are now all on the same partition, which wasnt the case before.
Which one is that? /tmp, /home/ws-content or something else? What is behind that partition: local to the VM, mounted through the network, which way (NFS, SMB, ...)?
> That change increased the performance
By how much? Could you post the Moodle Benchmark output? (Or, is it the prev. one with a score of 1904?)
> because files are not written from one partition to another. Right?
The benchmark output says clearly "Read (write) a file multiple times .. Moodle temp folder", which is /path/to/moodledata/temp.
> When i tested the performance whilst about 5 users where on the site the platform performace decreased drastically.
> I suppose there is still a somewhere a mistake in the settings but i cannot firgure it out. The server should not be the problem at least not when only 5 users are simpultaniously browsing. At least i would think that with 8 vCPU and 8 GB RAM.
Could be. Did you go through the https://docs.moodle.org/en/Performance_recommendations ?