I tried to back up a 60% full Ubuntu Linux RAID to a 4TB USB3 hard drive. I set the backup going and left it a few hours.
I was shocked to come back and find the RAID 100% full and only a few GB copied. It took me a few minutes to figure out what happened.
Maddeningly, the USB drive has a feature that it goes to sleep after 15 minutes or so, even if Ubuntu is actively using it to write files! Maybe the drivers on Windows do something that keep it awake, but on Linux it just goes to sleep in the middle of being used.
Now here's the thing, the drive DOES realize it has more to do and wake back up. But this sleep-wake causes a USB disconnect and reconnect. Which causes Ubuntu to unmount and remount the drive.
Now here's the problem, perhaps because the backup program is still making the the original mount point "busy", Ubuntu doesn't re-mount the media to the path. Instead it, gets mounted at "/media/path-1".
Since Linux uses regular folders as mount points, the old mount point at "/media/path" becomes a valid folder on the local disk. So the backup program keeps going, but now it's filling up the local disk.
I haven't found a solution for this problem that will allow me to complete a backup (or even complete a long-duration manual copy).
I was shocked to come back and find the RAID 100% full and only a few GB copied. It took me a few minutes to figure out what happened.
Maddeningly, the USB drive has a feature that it goes to sleep after 15 minutes or so, even if Ubuntu is actively using it to write files! Maybe the drivers on Windows do something that keep it awake, but on Linux it just goes to sleep in the middle of being used.
Now here's the thing, the drive DOES realize it has more to do and wake back up. But this sleep-wake causes a USB disconnect and reconnect. Which causes Ubuntu to unmount and remount the drive.
Now here's the problem, perhaps because the backup program is still making the the original mount point "busy", Ubuntu doesn't re-mount the media to the path. Instead it, gets mounted at "/media/path-1".
Since Linux uses regular folders as mount points, the old mount point at "/media/path" becomes a valid folder on the local disk. So the backup program keeps going, but now it's filling up the local disk.
I haven't found a solution for this problem that will allow me to complete a backup (or even complete a long-duration manual copy).