How to make a live disk snapshot

Community Support
1

Hi,

I like to make live disk snapshots while the system is running. I do not find a documentation that tells me what I need to configure, to get the ability of a live snapshot in Open Nebula.

Right now I am having a qcow2 datastore and qcow2 images. If I click on the snapshot while the machine is running I am getting an error “Error creating new disk snapshot: Cannot perform a live DISKSNAPSHOTCREATE operation”.

What do I have to do to get the live snapshot ability. Meaning making a snapshot while the VM is running. I like to get snapshots without interrupting the running system.

Thanks for your help!

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2

Hi,

Could you provide some more background info? OpenNebula version, datastores setup, etc.

Please provide the output from the following commands:

# <VM_ID> is the ID of the failing VM
onevm show <VM_ID> -x
onedatastore list -x
# both commands will output XML

It looks like that the VMM_MAD/TM_MAD pair is not found or not supported. But we need some more info to figure out what is going wrong.

Best Regards,
Anton Todorov

3

Hi Anton,

thanks for your reply. Thanks to your commands I found a mismatch between VM_MAD/TM_MAD pairs. After resolving this issue I could make live snapshot. Now it is kvm/qcow2 :wink: and not kvm/shared any longer.

But is there any documentation about what pair works with live snapshot and what pair does not? Did I missed in the documentation?

Kind regards,

Danny

4

Hi Danny,

I can’t find it in the docs either. This is relatively new feature so it looks like missing the corresponding docs. As storage addon contributor I am permanently tracking the code development mostly related to the storage so my “docs” are the sources where I discover such changes quickly.

The VM_MAD-TM_MAD pairs are configured in /etc/one/vmm_exec/vmmexecrc and the TM_MAD must have implemented snap_create_live.

EDIT: I’ve created issue #5038

Kind Regards,
Anton Todorov

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