Shared snapshots test
 

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

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Shared snapshots test
 

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

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Shared snapshots test
 

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




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