gmirror: replacing failed disks
Doug Poland
doug at polands.org
Sun Jan 16 12:14:17 PST 2005
Hello,
I've got a bootable gmirror running on identical SATA drives on
5.3-STABLE. The technique I've used to build the gmirror can be found
on http://people.freebsd.org/~rse/gmirror, under the heading "GEOM
mirror Approach 2: Single Slice, Preferred, More Flexible". Now I'd
like to experiment with replacing a "failed" drive. This particular box
has hot-swappable drives, so all I need to do is pull a drive out while
the box is running.
The man page states:
One disk failed. Replace it with a brand new one:
gmirror forget data
gmirror insert data da1
(My system has a provider gm0s1 with ad4 and ad6 as consumers, so I'll
use those device names)
Simulate ad4 failing:
pull the drive
put the drive back in, reboot if necessary to detect drive
# gmirror forget gm0s1
# dd if=/dev/zero of=/dev/ad4 bs=512 count=79
# size=`fdisk ad6 | grep ', size ' | head -1 | sed -e 's;^.*size \([0-9]*\).*$;\1;'` (echo "p 1 165 63 $size"; echo "a 1") | fdisk -v -B -f- -i /dev/ad4
OR
# fdisk -v -B -I /dev/ad4
# gmirror insert gm0s1 /dev/ad4s1
(Now wait two hours for the drives synchronize)
That should work, yes? How does gmirror know about /dev/ad4s1 if that
drive was previously unformatted or brand new?
--
Regards,
Doug
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