Server boot up problem all of the sudden

[RockDawg]

My current unRaid server has been running for about 2 years without issue.  I have it plugged into a CyberPower UPS.  I haven't tested it in some time but it has always worked and performs a clean shut down if the battery runs low the few times we experience a power outage.

 

Last night we had some pretty severe storms roll through and our power was out for around 2 hours.  More than long enough for the UPS batteries to run out and shut down the server.  When the power was restored the server wouldn't boot up correctly.  I would see the Supermicro logo for a few and then it would go to the BIOS screen for one of my LSI HBAs (I have 3) and then just sit at a black screen.  I tried reseating my RAM and even removed all but the minimum for it to boot and it still did the same.  Many reboot's and it acted this way everytime.

 

I finally gave up for the night around 10:30.  Not thinking I left it powered on at the black screen.  Strangely, I am lying in bed and at 11:45 I get an email from the Fix Common Problems plugin saying there are errors (minor things that don't relate to the boot issue).  This tells me that unRAID is now running.  

 

I haven't had time to attempt another reboot to see if it happens again,but why would it happen at all?  And if it does do it again, what the heck could cause the server to take over an hour to boot up into unRaid?  And where do I begin to troubleshoot the issue?