Shared snapshots test

Shared snapshots test

[Mikhail Klepachevskyy]

Hello!

I tried to test multisnapshots but unfortunately got some errors.
Here is what I did:

1) Build vanilla linux-2.6.33 kernel using Ubuntu Desktop 9.10
   config-2.6.31-19-generic config file with
   CONFIG_DM_MULTISNAPSHOT=m
   CONFIG_DM_MULTISNAPSHOT_MIKULAS=m
   CONFIG_DM_MULTISNAPSHOT_DANIEL=m
   lines added and with patches from http://people.redhat.com/mpatocka/patches/kernel/new-snapshots/r16/
   imposed.

2) reboot with new kernel

3) # modprobe dm-store-mikulas

   # modprobe dm-multisnapshot

   # pvcreate /dev/sdb

   # vgcreate vg1 /dev/sdb

   # lvcreate --size=500M --name=lv1 vg1

   # lvcreate --size=500M --name=lv2 vg1

   # dd if=/dev/zero of=/dev/mapper/vg1-lv2 bs=4096 count=1

   # 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

   # 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?

-- 
Best wishes,
Mikhail Klepachevskyy

Re: Shared snapshots test

[Mikulas Patocka]

Hi

You need to suspend and resume the origin device after create message and 
before attaching the snapshot.

> Hello!
> 
> I tried to test multisnapshots but unfortunately got some errors.
> Here is what I did:
> 
> 1) Build vanilla linux-2.6.33 kernel using Ubuntu Desktop 9.10
>    config-2.6.31-19-generic config file with
>    CONFIG_DM_MULTISNAPSHOT=m
>    CONFIG_DM_MULTISNAPSHOT_MIKULAS=m
>    CONFIG_DM_MULTISNAPSHOT_DANIEL=m
>    lines added and with patches from http://people.redhat.com/mpatocka/patches/kernel/new-snapshots/r16/
>    imposed.
> 
> 2) reboot with new kernel
> 
> 3) # modprobe dm-store-mikulas
> 
>    # modprobe dm-multisnapshot
> 
>    # pvcreate /dev/sdb
> 
>    # vgcreate vg1 /dev/sdb
> 
>    # lvcreate --size=500M --name=lv1 vg1
> 
>    # lvcreate --size=500M --name=lv2 vg1
> 
>    # dd if=/dev/zero of=/dev/mapper/vg1-lv2 bs=4096 count=1
> 
>    # 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?
> 
> -- 
> Best wishes,
> Mikhail Klepachevskyy

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/

Mikulas

Re: 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

Re: Shared snapshots test

[Busby]

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Hi,
     I used the patchs for LVM2.02.54, however, when i compiled it, an err
came:

../lib/liblvm-internal.a(lv_manip.o): In function `lv_extend':
lv_manip.c:(.text+0x629a): undefined reference to `last_seg'

  where is the 'last_seg' 's definition?
  my linux kernel version is 2.6.18.
  thank you!

best regards
Bubsy

2010/3/10 Mikhail Klepachevskyy <mikhailk1@open-e.com>

> 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
>
> --
> dm-devel mailing list
> dm-devel@redhat.com
> https://www.redhat.com/mailman/listinfo/dm-devel
>

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