I have a Dell PowerEdge 2900 that has been running 24/7 for nearly 18 months that rebooted unexpectedly today. OMSA doesn't show any errors, except that the RAID controller firmware is out of date, but that's been the case for months now.
Unfortunately I don't have a dump file to look through. OMSA reports all 4 DIMMs are "OK" as well as both CPUs. Both PSUs show OK. Temp shows 20 C. Voltage readings all show "Good".
I'm at a loss at this point, and this is a production server.
OMSA doesn't show any errors
Did you look in the Hardware Log?
What does Windows say as to the nature of the unexpected shutdown? Is there a stop code associated with it?
"The previous system shutdown at 12:18:37 on 8/6/2015 was unexpected." ID 6008
The hardware log is empty, nothing was logged when the reboot happened.
The alert log gives warnings about the RAID firmware version but that wasn't until after the reboot.
Windows did not generate any DMP files and I have no record of a stop error code.
Not really. There should be SOME thing, SOME where. The absence of stop codes, kernel, or other errors would indicate a hardware issue, but the lack of events in the hardware log would indicate there are no hardware issues.
I might start by updating all the system firmware and drivers, then update your version of OMSA, then wait for it to happen again. You could run full 32-bit Diagnostics, but it's unlikely to find any failing hardware with it being intermittent like that, especially as spread out as they would be.