> is there an instruction document how to exacly host the ELOG on a server for example a raspberry pi?

would be same as on any other linux machine, in the nutshell:

- install generic raspbian (R-12 is current version)
- setup the network
- setup apache2 https with automatic https certificate renewal using certbot
- setup apache2 redirect to elogd port 8080
- setup elogd on port localhost:8080

some of this is written up here:
https://daq00.triumf.ca/DaqWiki/index.php/Ubuntu#Install_apache_httpd_proxy_for_midas_and_elog

in theory you can run elogd without apache https proxy, but I find computer security
people are quite happy when I tell them that I run apache https with SSLlabs score "A+".

also I believe elogd does not support automatic https certificate renewal, running
it behind apache https solves that.

another consideration, specifically for RaspberryPi, they use SD flash for storage,
and unlike SATA and NVMe SSDs, SD flash does not have SMART to report flash read,
write and wear-out problems. So you may run into unexpected SD flash failures. We do.

do daily/hourly rsync to backup/archive storage to avoid total data loss if this happens.

also be aware that SD flash is very slow, compared to normal PC SSDs. read speed is not too
bad, but write speed is quite abysmal.

as solution to this, RPi5 can have a PCIe/NVMe dongle, you can try that instead of SD flash.

K.O.