Today I also had a failing upload from the app on my ipad. It was working before, but since that I have modified my system a lot (upgrades etc)…
The app version is 184.108.40.206 and my NC server is 20.0.8, Ubuntu 20.04 and php 7.4.
Anyway, the file was about 500 MB.
I noticed that the file was saved to both
/tmp (default php upload directory) as
/tmp/phpxw9sqS and in my nextcloud directory as
/tmp partition is only 256 MB so when it got full the temporary files were removed and the upload retried.
The logs in nextcloud admin settings gave these errors:
Error no app in context Sabre\DAV\Exception\BadRequest: Expected filesize of 551250667 bytes but read (from Nextcloud client) and wrote (to Nextcloud storage) 268414976 bytes. Could either be a network problem on the sending side or a problem writing to the storage on the server side.
Error PHP Error: fread(): write of 8192 bytes failed with errno=28 No space left on device at /var/www/nextcloud/apps/files_external/3rdparty/icewind/streams/src/Wrapper.php#91
The solution for me was to change the temporary upload directory for php in
/etc/php/7.4/fpm/php.ini in my case).
Have you checked your php settings?
Which nc version are you running?