[CentOS] Unusual System State

Wed Dec 7 21:46:29 UTC 2016
Chris Olson <chris_e_olson at yahoo.com>

Our smallest network of systems has only four computers connected
via Gigabit Ethernet.  The oldest and most stable platform is an eight
year old Dell E520 running CentOS 6.8.  We often try out applications
on this Dell/CentOS machine before moving them to other systems on our
other networks.

Last night, one of our users decided to create a single, 228GB home
directory tar archive on an empty, 500GB, external, USB, Ext4 disk
drive. This was obviously a poor decision. The extent of the results
were not obvious until this morning.

All disk activity had stopped and the system appeared to be hibernation.
A push on the power button usually brings the system back to life, but
in this case, the unlock screen was presented for only three seconds
and then the hibernation mode was resumed.  Repeated attempts to log
on were all thwarted due to this behavior.  ssh from other systems wasalso not possible.

Holding the power button in order to initiate power down did not work
either.  The result was the same as a one second press of front panel
power button bringing up the unlock screen for only a short time.  We
eventually removed the power cord for five minutes and then restarted
the machine.

The system is running normally once again.  The corrupted file system
on the USB disk has been restored by re-partitioning and building a new
Ext4 file system on it. The user no longer gets to use external disks.

Examination of log files and the dmesg output did not yield any useful
information regarding the unusual state of the system when unlock logon
was not possible.  Is there somewhere else we should look for evidence
of what actually happened and the unusual state of the system.  Thanks.

[user at computer ~]$ uname -a
Linux computer 2.6.32-642.11.1.el6.x86_64 #1 SMP Fri Nov 18 19:25:05 UTC 2016
x86_64 x86_64 x86_64 GNU/Linux
[user at computer ~]$