[dm-devel] Shared snapshots test

[Mikhail Klepachevskyy]

Hello!

Big thanks! It helped!


On Wed, Mar 10, 2010 at 08:11:11AM -0500, Mikulas Patocka wrote:

> 
> You need to suspend and resume the origin device after create message and 
> before attaching the snapshot.
> 
> > I tried to test multisnapshots but unfortunately got some errors.
> > Here is what I did:
> > 

<skip>

> >    # echo 0 `blockdev --getsize /dev/mapper/vg1-lv1` multisnapshot \
> >      /dev/mapper/vg1-lv1 /dev/mapper/vg1-lv2 16 0 mikulas 0\
> > 	 | dmsetup create ms
> > 
> >    # dmsetup message /dev/mapper/ms 0 create
> 
> dmsetup suspend ms
> dmsetup resume ms
> 
> >    # echo 0 `blockdev --getsize /dev/mapper/vg1-lv1` multisnap-snap \
> >      /dev/mapper/vg1-lv1 0 | dmsetup create ms0
> > 
> > At this point I got the next error:
> > device-mapper: reload ioctl failed: No such file or directory
> > Command failed
> > 
> > And these lines appeared in dmesg:
> > [ 6876.506623] device-mapper: table: 252:3: multisnap-snap: Snapshot with this id doesn't exist
> > [ 6876.506629] device-mapper: ioctl: error adding target to table
> > 
> > Could you check all the steps I performed right and what could cause
> > those error messages?
> > 
> 
> But rather, you could use userspace support for shared snapshots, it makes 
> the use much easier, you can use lvcreate, lvremove, lvresize commands:
> 
> for lvm-2.02.54: 
> http://people.redhat.com/mpatocka/patches/userspace/new-snapshots/lvm-2.02.54/
> for lvm-2.02.60:
> http://people.redhat.com/mpatocka/patches/userspace/new-snapshots/lvm-2.02.60/
> for lvm-2.02.62:
> http://people.redhat.com/msnitzer/patches/multisnap/lvm2/LVM2-2.02.62/

-- 
Best wishes,
Mikhail Klepachevskyy