Hi guys. It's a long time since I've posted here, but recently I've had a lot of silent errors when transferring backup image files to external USB hard drives (usb powered drives).
The HDD media itself seems to be fine and the drives themselves in good condition (when viewing SMARTs etc), and the copy operation appears successful with no warning of the failure (from windows 7). However, when I run a checksum (hash) on the copied files there is sometimes an error.
I first noticed this when I needed to restore an image and found it to be corrupt. I did some testing and found that several of my other image files were also corrupt. So then I started using sha type checksums to verify each time I copied, and an alarmingly high percentage (like several percent depending on the motherboard usb hardware and the usb drive combination) fail the checksum but report no error while copying.
This is pretty surprising and alarming to me! At first I thought it was one particular hardware combination, a Gigabyte motherboard and a Seagate external (usb powered) HDD. Well that combination was probably the worst, with about a 5 to10 percent chance of one of these silent write errors per 2GB image file, but I've since noticed other combinations of motherboard and external usb drives giving the same issue (though with lower probability).
For now I'm still using these drives to save my backup images, but I'm checksuming every file after every copy. Anyway, just wondering if any other users have had data integrity problems like this with external usb (usb powered) hard drives?