Hello mira,
thank you for your prompt reply.
We get similar errors in kern.log like:
EXT4-fs error (device md2): ext4_find_extent:920: inode #46137352: comm kvm: pblk 73081648 bad header/extent: invalid magic - magic 0, entries 0, max 0(0), depth 0(0)
How can we rescue the VMs without data...