Nextcloud tmp files location

Hi,

Just installed Nextcloud on RaspberryPi4 running Raspbian.
The data location is external USB3.0 Hard Drive.
However I noticed whenever I upload a file, there is no HDD activity until the file is fully uploaded.
Nextcloud must be storing this somewhere temporarily (presumably in /var/www… area).
On RPI, this area is microSD card. I am worried that microSD card may get corrupted after many files are uploaded (due to low write cycle life of SD).

Which folders would need to move to external HDD to avoid this problem?

You should have a look at the tempdirectory setting in the config.php:
https://docs.nextcloud.com/server/16/admin_manual/configuration_server/config_sample_php_parameters.html

Thanks for the help!