Read SMART status on Windows Server 2008 R2

Yes, I have encountered this with low-end cards and buggy drivers. However, no, not on an up-to-date Adaptec rebranded card. Wow is all I can say. One thing to consider, maybe it is more a bug with the drive than the RAID controller.

I don't have a good answer, but since you seem to have exhausted most of your options other than replacing the card, (and replacing the drives did the trick) here's a few ideas you can consider for your troubleshooting:

• The WD drives were RE (RAID Edition) drives, right? The time limited error recovery is important, so if you don't have that and the drive is attempting to recover the sector, you are going to get a looooong pause from that drive. If the RAID controller is being patient and not dropping the drive you'll have a big problem on your hands.

• Check the SMART data on the drives you removed and see if there is anything interesting.

Another comment about the importance of time limited error recovery (TLER) feature, from NAS / RAID vendor support:

As I mention before, we always suggest customers to use enterprise level drives if they use the drives in RAID settings. Enterprise level drives have more consistent responding time so that the RAID will be safer.

From the man page (change the detials to suite your setup):

smartctl -a -d megaraid,0 /dev/sdb