And happy new year.
I had thought this was something involving Gaussian09 memory usage until I restarted a machine and found the same problem occurring in Ubuntu. Below is a quick fix (and reminder for the future).
Checking disk space with df -all :
user@machine:~$ df -all Filesystem 1K-blocks Used Available Use% Mounted on /dev/sda1 147550696 5863896 134191632 5% / proc 0 0 0 - /proc none 0 0 0 - /sys none 0 0 0 - /sys/fs/fuse/connections none 0 0 0 - /sys/kernel/debug none 0 0 0 - /sys/kernel/security none 3053752 260 3053492 1% /dev none 0 0 0 - /dev/pts none 3058264 0 3058264 0% /dev/shm none 3058264 84 3058180 1% /var/run none 3058264 0 3058264 0% /var/lock none 3058264 0 3058264 0% /lib/init/rw none 0 0 0 - /var/lib/ureadahead/debugfs nfsd 0 0 0 - /proc/fs/nfsd binfmt_misc 0 0 0 - /proc/sys/fs/binfmt_misc
… we find /var/lib/ureadahead/debugfs both existing but taking up no space to speak of. Several seconds later (after a reboot), we find the following…
user@machine:~$ df -all Filesystem 1K-blocks Used Available Use% Mounted on /dev/sda1 147550696 5864268 134191260 5% / proc 0 0 0 - /proc none 0 0 0 - /sys none 0 0 0 - /sys/fs/fuse/connections none 0 0 0 - /sys/kernel/debug none 0 0 0 - /sys/kernel/security none 3053752 260 3053492 1% /dev none 0 0 0 - /dev/pts none 3058264 0 3058264 0% /dev/shm none 3058264 84 3058180 1% /var/run none 3058264 0 3058264 0% /var/lock none 3058264 0 3058264 0% /lib/init/rw none 147550696 5864268 134191260 5% /var/lib/ureadahead/debugfs nfsd 0 0 0 - /proc/fs/nfsd binfmt_misc 0 0 0 - /proc/sys/fs/binfmt_misc
Properly updated machines (as per below) both do not contain this /var/lib/ureadahead/debugfs directory and do not subsequently "blow up" and eat disk space (to date. This may not be the real problem, but disk space usage will increase to +60% and, to my mind, the machine will noticeably slow down).
Fix Steps:
sudo aptitude update sudo aptitude upgrade
Update your 10.04. Some web pages report that the problem with /var/lib/ureadahead/debugfs is attributable to a bug in mountall (now fixed. See bugs.launchpad.net/ubuntu/+source/mountall/+bug/736512).
sudo mv /etc/init/ureadahead.conf /etc/init/ureadahead.conf.disable
If you do NOT perform this move, the machine restart will produce the same /var/lib/ureadahead/debugfs error above. Kudos to ubuntuguide.net/howto-fix-ureadahead-problem-after-upgrading-to-ubuntu-10-04 for pointing this out.
sudo shutdown -r now
System restart, problem (for me, at least) solved.