I have an interesting issue.  All of my drives are present, working, parity checked, valid, etc.  No major issues what so ever, and then I reboot the system....  Every time I reboot, no matter how long in between reboots (weeks or minutes), 4 drives are missing so the server is not working.  To fix the problem, I immediately just reboot it again and the drives are there (I'm almost positive it's the same 4 drives every time as well: 12, 13, 16, 19).  If I reboot it again, they'll be gone, so I reboot again to fix it.  Four drives every time (internally, these are not all attached to the same card either) - I've attached two syslogs showing this issue.  It's not a big deal since it's easily fixable on my end (just reboot again), but it is extremely bizarre.

 

By the way, this happened for me in 4.6 and is happening again in 4.7 (what I'm presently running), although it never happened to me in older versions, but then I also only had a total of 16 disks in the array, where now I have 20.

 

My go script is empty except for it asking to load unmenu, which I've taken out and the issue still occurs.

 

syslog-2012-01-23-missingdrives.txt

syslog-2012-01-23-drivesreappear.txt

Power supply issue maybe? What PSU are you using?

Corsair TX 750Watt.  I think I have a power supply tester laying around somewhere, but I can't say that I've ever used it.  I'll have to look into it - thanks for the idea.