Ubuntu installed on Xeon E3 shutdown out of sudden?

In recent installation of Ubuntu 12.10 on Intel Xeon E3-1200 V1 system, I have encountered random shutdown out of no reason. The most obvious symptom I can observe is the HDDs running on RAID10 would first go down before the system is completely power off.

Steps that I have done to troubleshoot including:

• unplug & plug all the HDDs.
• relocate all SATA cables
• relocate the RAM to another slot
• change power cord
• check CPU temperature

Nothing solved the problem. I then reset the BIOS.

Before power up the server, reading the manual of motherboard I realize the Execute Disable Bit seems not officially supported on Ubuntu. I then disable the function.

Everything seems working fine afterwards. I have not tested whether it is the BIOS which caused the problem or the Execute Disable Bit create the problem, but if you do encounter the same problem like I did, try disable it. May save your day. =)