That all worked beautifully. Right up until I left the BackupPC running 
against a RAID array with a bad disk.

It failed again after about 30 hours. The symptoms are the same.

I think I need to bring the array back up but leave that disk offline with:

mdadm --assemble --force /dev/md0 /dev/sdb /dev/sdc

(sdd is the bad drive)

Then follow the remainder of the steps to check.

I have a new disk on the way. I would then add this new disk into the 
array and sync.

Does that sound correct?

Rob

On 13-09-15 09:12 PM, Phil Turmel wrote:

Hi Robert,

On 09/15/2013 04:42 PM, Robert Schultz wrote:

quoted

Phil:

Thank you for the information. This is my backup machine. Up to this
point I wasn't concerned about having a second copy of this machine, but
I have a tendency to decommission a computer and leave the backups on by
backuppc for archive purposes. I probably don't really, really need
anything on this PC. That said I'm am very paranoid that I will have
some other failure before I can resolve this :-(

I hadn't read anything about timing in disks in RAID - I'll have to go
do some research. I see WD has their RED series that appears to be
directed to this market.

Please do read the archives on the topic.  You won't regret it.

And yes, the WD REDs power up with SCTERC set properly.  I bought four
of these for my new media server.

quoted

Here is the information requested. Please let me know if this changes
anything in your instructions. I'll hold off until you confirm.

One modest change.  Two of your drives *do* support SCTERC, they just
have to have it enabled on every powerup:

quoted

SCT Error Recovery Control:
            Read: Disabled
           Write: Disabled

For those two drives, your boot sequence should have:

smartctl -l scterc,70,70 /dev/sdX

For the other, you still need:

echo 180 >/sys/block/sdX/device/timeout

Otherwise, my recommendations stand.

Phil