Re: Backup of vm disk images

On Wed, Apr 22, 2020 at 07:51:09AM +0200, Anders Östling wrote: Hi Anders, The kvm(a)vger.kernel.org mailing list is mostly for the discussion and development of the KVM kernel module so you may not get replies. I have CCed libvir-list and developers who have been involved in libvirt backup features. A naive cp(1) command will be very slow because the entire disk image is copied to a new file. The fastest solution with cp(1) is the --reflink flag which basically takes a snapshot of the file and shares the disk blocks (only available when the host file system supports it and not available across mounts). Libvirt's backup commands are more powerful. They can do things like copy out a point-in-time snapshot of the disk while the guest is running. They also support incremental backup so you don't need to store a full copy of the disk image each time you take a backup. I hope others will join the discussion and give examples of some of the available features. Stefan