Internal error from Redmine turns out to be due to tmp directory being full

This helpful error:

Internal error An error occurred on the page you were trying to access. If you continue to experience problems please contact your redMine administrator for assistance.

When looked into the logs:

sudo tail -f /var/log/redmine/default/production.log

cannot generate tempfile `/tmp/RackRewindableInput20111102-20138-rbbyah-9'
/usr/lib/ruby/1.8/tempfile.rb:52:in `initialize'
/usr/lib/ruby/1.8/rack/rewindable_input.rb:73:in `new'
/usr/lib/ruby/1.8/rack/rewindable_input.rb:73:in `make_rewindable'
/usr/lib/ruby/1.8/rack/rewindable_input.rb:26:in `read'
/usr/lib/ruby/1.8/rack/request.rb:147:in `POST'
/usr/lib/ruby/1.8/rack/methodoverride.rb:15:in `call'
/usr/lib/ruby/1.8/action_controller/params_parser.rb:15:in `call'
/usr/lib/ruby/1.8/action_controller/session/cookie_store.rb:93:in `call'
/usr/lib/ruby/1.8/action_controller/failsafe.rb:26:in `call'
/usr/lib/ruby/1.8/rack/lock.rb:11:in `call'
/usr/lib/ruby/1.8/rack/lock.rb:11:in `synchronize'
/usr/lib/ruby/1.8/rack/lock.rb:11:in `call'
/usr/lib/ruby/1.8/action_controller/dispatcher.rb:106:in `call'
/usr/lib/ruby/1.8/rack/content_length.rb:13:in `call'
/usr/lib/ruby/1.8/rack/handler/fastcgi.rb:57:in `serve'
/usr/share/redmine/vendor/rails/railties/lib/fcgi_handler.rb:103:in `process_request'
/usr/share/redmine/vendor/rails/railties/lib/fcgi_handler.rb:153:in `with_signal_handler'
/usr/share/redmine/vendor/rails/railties/lib/fcgi_handler.rb:101:in `process_request'
/usr/share/redmine/vendor/rails/railties/lib/fcgi_handler.rb:78:in `process_each_request'
/usr/share/redmine/vendor/rails/railties/lib/fcgi_handler.rb:77:in `each'
/usr/share/redmine/vendor/rails/railties/lib/fcgi_handler.rb:77:in `process_each_request'
/usr/share/redmine/vendor/rails/railties/lib/fcgi_handler.rb:76:in `catch'
/usr/share/redmine/vendor/rails/railties/lib/fcgi_handler.rb:76:in `process_each_request'
/usr/share/redmine/vendor/rails/railties/lib/fcgi_handler.rb:51:in `process!'
/usr/share/redmine/vendor/rails/railties/lib/fcgi_handler.rb:23:in `process!'
/usr/share/redmine/public/dispatch.fcgi:24

Well maybe it cannot create the temporary file simply because it is out of space. Let's check:

df -h

Yup.

Filesystem Size Used Avail Use% Mounted on
/dev/mapper/simone-root
322M 130M 176M 43% /
tmpfs 1007M 0 1007M 0% /lib/init/rw
udev 1002M 116K 1001M 1% /dev
tmpfs 1007M 0 1007M 0% /dev/shm
/dev/vda1 228M 19M 198M 9% /boot
/dev/mapper/simone-home
9.9G 3.3G 6.1G 36% /home
/dev/mapper/simone-tmp
368M 349M 0 100% /tmp
/dev/mapper/simone-usr
4.6G 1.4G 3.1G 31% /usr
/dev/mapper/simone-var
40G 25G 13G 67% /var
/dev/mapper/simone-srv
20G 6.1G 13G 33% /srv

Let's get rid of some of that, what appears to be the bulk from an ls -la /tmp.

sudo rm -rf /tmp/file*

And Redmine works again!