We have the same issue, in a short time a lot of data (hundreds of GB) was written in the same folder.
It seems it has something to do with the automated backup schedule, when I analyze the time of the
new files and folders in that directory. Is it possible to prevent Moodle from writing this amount of
data in the Moodle data store? We use Moodle 3.1.5+
Hi,
The moodledata/temp/backup directory is used (temporarily) when a backup of a course is made. If something goes wrong doing the backup, the data are not deleted from there, and it can take a lot of space if lot of backups are going wrong
You can delete everything from this directory, and then check next backups, to find the origin of the problem, and correct it.
HTH,
Séverin