On 12/28/11 20:06, Jeremy Thompson wrote:

The RAID array consists of drives that are on cheap SATA controllers
no RAID function on them.  That is why I chose to use mdadm instead of
a true RAID card.

Me too, I meant 3ware used as classic sata controller

So the errors would happen regardless if heat was an issue?

I think that with temperature you would get a different error: disk 
going completely offline due to thermal shutdown.
Anyway Gordon showed you how to check for temperatures; try that.
Another way is via "smartctl -a /dev/sdX"

SCSI errors are usually due to cabling, not perfect firmware, not 
perfect controller, not perfect controller drivers.
If you show us the exact error we can be a bit more precise.
Note: 5 retries (for each scsi command) by the SCSI layer also applies 
to SATA disks, which is your case

I'll wait until the reshape is done then, shutdown the machine and
re-arrange the drives before I add another drive to the array.

Yes this would be my suggestion, but I don't know everything.

Have a look at the temperatures though, and compare to max temp by your 
HDD specs. I suggest you don't stop the array if they are lower.