The droplet on Digital Ocean for my Rails project did not have any space left.
Here is how I created space by deleting files.
1. Login using SSH and check available space using $df -h
2. Check disk usage using du command.
$du -h | sort -h
This will list the directories showing the biggest size at the bottom.
I noticed that ./project/shared/log folder was consuming 3.3GB space.
3. In another terminal window, I opened sftp session.
4. sftp>cd project/shared/log
5. Now delete files using rm command.
Everything was fine after that.