Mac Pro RAID drive 4 disappears
I have a Mac Pro RAID card in my Mid-2010 Mac Pro. It's worked flawlessly for years, but recently I had a serious slowdown problem and drives were disappearing, so I bit the bullet, bought four new drives, replaced them all, rebuilt the RAID and restored from backup. This worked fine for about 3 days, then I needed to reboot, and when the computer came back up from the reboot, the drive in Bay 4 was gone. I could not see it in any utility. I tried powering down and reseating it repeatedly but no matter what I did the computer could not see it. Figuring it had to be a fluke failure of a new drive, I obtained a spare and replaced it. The computer came up and recognized the new drive, so I added it to the RAID and waited the nearly WEEK it takes to rebuild, which finished two days ago, then today I need to reboot, and when the computer came back up, the drive in Bay 4 is gone AGAIN.
This RAID card has a relatively new battery that tests good. It is operating fine other than this bizarre issue. Any ideas?
Thanks,
H.
Mac Pro (Mid 2010), OS X Mountain Lion (10.8.2), 16G RAM, Mac Pro RAID card in 0+1