Re: [libvirt] libvirt external snapshot error

The file should not exist prior to the snapshot. If you want to pre-create it (with correct size and format), you need to specify --reuse-external in that case. Virsh manual already documents that: If --reuse-external is specified, and the snapshot XML requests an external snapshot with a destination of an existing file, then the destination must exist and be pre-created with correct format and metadata. The file is then reused; otherwise, a snapshot is refused to avoid losing contents of the existing files.