[ale] Software RAID1 rebuild after HDD failure (How to do?)

[David Corbin]

On Friday 30 June 2006 08:42 pm, Jim Popovitch wrote:
> Joe Steele wrote:
> > By way of comparison:  when first building a new raid array, you
> > partition the drives, then you run mdadm to assemble the array.  Only
> > then do you format the assembled array.  The device that gets formated
> > is /dev/md0 (the raid device), not /dev/hda1 (a partition that is part
> > of the array).
> >
> > If a drive fails, its partition(s) are removed from the array, a new
> > drive is installed with partitions of the same size as those of the
> > failed drive, and the partition(s) are added back to the array.  At that
> > point, the raid system begins to rebuild the data on the partitions,
> > which includes rebuilding whatever formatting belongs there.
>
> Good point Joe.  Ryan, just make sure you don't re-format /dev/md0, let
> mdadm sync the data from the first drive to the second drive. ;-)

and once you do, you can monitor progress with "cat /proc/mdstat".