Table of Contents
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Proxmox KVM : How to restore files from dump/backup
Just a simple procedure that was a bit tricky to find on the web. I needed to restore a few files that got overwritten on a server which is a KVM virtual machine running on a Proxmox host. They are several ways to achieve this but I found this to be the simplest and cleanest way :
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Do a manual restore by using a non existing VMID (YYY): qmrestore dump/vzdump-qemu-XXX-DATE-TIME.vma YYY
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Mount the partition : modprobe nbd max_part=16 qemu-nbd --connect=/dev/nbd0 images/YYY/vm-YYY-disk-1.qcow2 vgscan Reading all physical volumes. This may take a while... Found volume group "vgmain" using metadata type lvm2 Found volume group "pve" using metadata type lvm2 vgchange -ay vgmain 2 logical volume(s) in volume group "vgmain" now active mount /dev/vgmain/root /mnt/XXX
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Do not forget to unmount the drive afterwards : umount /mnt/XXX vgchange -an vgmain qemu-nbd -d /dev/nbd0 /dev/nbd0 disconnected rmmod nbd
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You can then remove wour fake VM if you do not need to recover any more files : qm destroy YYY
Troubleshooting
If vgscan doesn’t return anything and a manual partprobe returns the
following :
partprobe /dev/nbd0
Error: Error informing the kernel about modifications to partition /dev/nbd0p1 -- Invalid argument. This means Linux won't know about any changes you made to /dev/nbd0p1 until you reboot -- so you shouldn't mount it or use it in any way before rebooting.
Error: Failed to add partition 1 (Invalid argument)
then you have forgotten to add the max_part parameters to your
modprobe command