hello

We run a several KVM who can't be turned off. But i need to take a back-up of it. The images of virtual machines are stored on a NAS. There is no LVM installed so LVM snapshots are not possible. Do you know any other possibility to achieve this without pause or shutdown the machines.

Thank you

1. backup agents in the VM
2. sync the disk image with a side image and back that up
3. pause VM, copy disk, unpause. should be fast and might be fast enough for nobody to notice the downtime
4. use qcow2, make a qcow snapshot, back up the chain before snapshot

Yes I found that possibility to
But the VM's are in use al the time so pause or shutdown is not acceptable
I found something named QEMU livebackup but i haven't try something like this
do you have some experience with this feature of QEMU?

There is also live state backup software available in linux in commercial form.

What software do you suggest?
Whe prefer a open-source and free solution for this

That's just one option, I provided 4

What option do you prefer if we don't want any down time
We need an option that don't touch the performance of the machines
And how can you realise that option.
Is that with a program or script?

thanks

You'd have to look up what might suit your needs. I have only seen a couple of companies that offer a live state. You would either need to use kvm/qcow type tools that use virtual support or install some software that would act on the virtual hard drive just as if it were a stand alone computer.

This is one of them but you'd need lvm. http://www.storix.com/ It may be that you would have to re-create the systems and use lvm or btrfs or zfs. Otherwise the tools for kvm/qemu would have to do.

The only other way is to use some rsync sort of deal. This nas box also may have some features that could be used. Some of the advanced nas boxes have all sorts of options.

Unless things have changed, you can not(*should not rather) use LVM to create snapshots containing Virtual Guests because the LVM can not guarantee a consistent state of the Guest's filesystem.