ownCloud uses chunking for uploads by authenticated users. These chunks will be uploaded into the users uploads folder. It is also possible to change the upload storage to some temp folder in the system.
However you need to make sure that there is enough storage available for all uploads happening concurrently. Once the upload is finished the chunks are being assembled into the actual file and put into the actual storage.
If an upload is aborted due to any reasons the chunks won’t be cleaned up automatically. Therefore it is crucial to run the following occ command regularly on any ownCloud system:
occ dav:cleanup-chunks
I would recommend to use cron to run this command at least once a day. Configure it like the typical system cron, for example like so (paths could differ):
# /etc/cron.d/owncloud - Debian based system
37 0 * * * www-data /usr/bin/php /var/www/owncloud/occ dav:cleanup-chunks
# or alternatively directly as a www-data user cron by running `crontab -e -u www-data`
37 0 * * * /usr/bin/php /var/www/owncloud/occ dav:cleanup-chunks
# replace www-data with apache on RHEL based systems
EDIT: Links to relevant documentation:
- https://doc.owncloud.com/server/admin_manual/configuration/server/occ_command.html#dav-commands
- https://doc.owncloud.org/server/admin_manual/configuration/server/background_jobs_configuration.html#cleanupchunks
- https://doc.owncloud.com/server/admin_manual/configuration/files/big_file_upload_configuration.html#configuring-php