Backuping "special" snapshots

Hi list,

I am searching a way to backup a "special" logical volume. This special lv doesn't contains a filesystem, it contains a hole image disk of a running server (MBR,Partition Table, Partitions and filesystems), in fact it is a VBD (Virtual Block Device) of a HVM Xen Guest.

I want to be able to make the backup without shutting down the Virtual Machine, but the traditional way :

- make a snapshot
- mount snapshot
- backup the snapshots
- umount snapshot
- remove snapshot

is not suitable for this kind of logical volumes.

I search some information about it, but the only clue is:

fdisk -l -u /dev/vg00/lv00

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Quoted 16 lines · Marc Patino G�mez

Hi list,

I am searching a way to backup a "special" logical volume. This special lv doesn't contains a filesystem, it contains a hole image disk of a running server (MBR,Partition Table, Partitions and filesystems), in fact it is a VBD (Virtual Block Device) of a HVM Xen Guest.

I want to be able to make the backup without shutting down the Virtual Machine, but the traditional way :

- make a snapshot
- mount snapshot
- backup the snapshots
- umount snapshot
- remove snapshot

Quoted 6 lines

is not suitable for this kind of logical volumes.

I search some information about it, but the only clue is:

fdisk -l -u /dev/vg00/lv00

Hi Marc,

You can use the kpartx tool for this. It was originally written as part of multipath-tools and it allows you to map the partitions on a device-mapper device like an LVM2 logical volume.

E.g. you would run:

# kpartx -a /dev/vg00/lv00

And that will scan lv00 for partitions and create new devices in /dev/mapper named lv00p1, lv00p2, ... that you can then use to access the content of the partitions.

When you're done, run:

# kpartx -d /dev/vg00/lv00

To remove the temporary kpartx maps.

Regards,
Bryn.

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Quoted 16 lines · Marc Patino G�mez

Hi list,

I am searching a way to backup a "special" logical volume. This special lv doesn't contains a filesystem, it contains a hole image disk of a running server (MBR,Partition Table, Partitions and filesystems), in fact it is a VBD (Virtual Block Device) of a HVM Xen Guest.

I want to be able to make the backup without shutting down the Virtual Machine, but the traditional way :

- make a snapshot
- mount snapshot
- backup the snapshots
- umount snapshot
- remove snapshot

Quoted 6 lines

is not suitable for this kind of logical volumes.

I search some information about it, but the only clue is:

fdisk -l -u /dev/vg00/lv00

Hi Marc,

You can use the kpartx tool for this. It was originally written as part of multipath-tools and it allows you to map the partitions on a device-mapper device like an LVM2 logical volume.

E.g. you would run:

# kpartx -a /dev/vg00/lv00

And that will scan lv00 for partitions and create new devices in /dev/mapper named lv00p1, lv00p2, ... that you can then use to access the content of the partitions.

When you're done, run:

# kpartx -d /dev/vg00/lv00

To remove the temporary kpartx maps.

Regards,
Bryn.

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=+xgZ
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_______________________________________________
linux-lvm mailing list
[email protected]
https://www.redhat.com/mailman/listinfo/linux-lvm
read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/

Hi again,

I try kpartx and it's so cool, but I can't make snapshots of /dev/vg00/lv00p1 ... so I can't solve the problem of making backup without stopping the Virtual Machine.

Any advice?

Regards,

Marc

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Quoted 6 lines · Marc Patino G�mez

Hi again,

I try kpartx and it's so cool, but I can't make snapshots of /dev/vg00/lv00p1 ... so I can't solve the problem of making backup without stopping the Virtual Machine.

Quoted 7 lines

Any advice?

Regards,

Marc

Sorry, I thought that lv00 was the snapshot. Just create a snapshot of it (e.g. lv00-snap) and run kpartx against that instead.

Cheers,
Bryn.

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_______________________________________________
linux-lvm mailing list
[email protected]
https://www.redhat.com/mailman/listinfo/linux-lvm
read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/

I try kpartx and it's so cool, but I can't make snapshots of /dev/vg00/lv00p1 ... so I can't solve the problem of making backup without stopping the Virtual Machine.

Any advice?