On Mon, Oct 20, 2008 at 03:28:07PM +0530, rishi agrawal wrote:
> Hello Everyone,
>
> I would like to know about the use of "losetup".
>
> By use I want mean that in what all situations will I use losetup. Its
> okay that it attaches a loop device to any regular file but how do we
> use this feature.
Anytime you use the option loop to mount, you use (indirectly) losetup:
mount -o loop,ro distro.iso /mnt
It is also useful for temporary/test block devices. For instance, a
snapshot:
dd if=/dev/zero of=snapshot bs=1 count=0 seek=4G
dev=$(losetup -fs snapshot)
echo 0 $(blockdev --getsize /dev/sda) snapshot /dev/sda $dev P 16 |
dmsetup create snapshot
e2fsck -yf /dev/mapper/snapshot
Also joining a disc image together:
declare -a loops
for i in sda.img.*; do
loops+=($(losetup -fs $i))
done
size=0
for l in ${loops[*]}; do
bsize=$(($(blockdev --getsz $l)+size))
echo $size $bsize linear $l 0
size=$bsize
done | dmsetup create image
mount /dev/mapper/image /mnt
--
Luciano Rocha <luciano@xxxxxxxxxxx>
Eurotux Informática, S.A. <http://www.eurotux.com/>
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