How to understand which folders need to be backed up and which services to disable for this?

Question

Backup

I didn’t come across linux, how to backup files correctly and which ones so that everything works when restoring?
I have php, apache, nextcloud. I set up backup via Duplicati, I archive the database via mysqldump to a file and add it to the main backup, but how to stop Apache, php correctly so that there are no conflicts during executable files?
I found information that you should not backup the sys tmp proc folders. Who will guide me on the right path?

Answer 1

Well, look, if you have php, apache, nextcloud + mysql
, then we have important data:
database (there are nextcloud settings and service things)
nextcloud files (site
files) nextcloud user files (their photos, files, etc.)
apache settings and php
for a restful sleep, you need to regularly back up user data and the database
files of the nextcloud itself and the apache + php settings optionally (for example, back up every time before updating the version)
it makes no sense to back up all other files on the server.