+This mode provides the lowest operation downtime, at the cost of a
+small inconstancy risk. It works by performing a Proxmox VE live
+backup, in which data blocks are copied while the VM is running. If the
+guest agent is enabled (`agent: 1`) and running, it calls
+`guest-fsfreeze-freeze` and `guest-fsfreeze-thaw` to improve
+consistency.
+
+A technical overview of the Proxmox VE live backup for QemuServer can
+be found online
+https://git.proxmox.com/?p=pve-qemu.git;a=blob_plain;f=backup.txt[here].
+
+NOTE: Proxmox VE live backup provides snapshot-like semantics on any
+storage type. It does not require that the underlying storage supports
+snapshots. Also please note that since the backups are done via
+a background Qemu process, a stopped VM will appear as running for a
+short amount of time while the VM disks are being read by Qemu.
+However the VM itself is not booted, only its disk(s) are read.
+
+.Backup modes for Containers:
+
+`stop` mode::
+
+Stop the container for the duration of the backup. This potentially
+results in a very long downtime.
+
+`suspend` mode::
+
+This mode uses rsync to copy the container data to a temporary
+location (see option `--tmpdir`). Then the container is suspended and
+a second rsync copies changed files. After that, the container is
+started (resumed) again. This results in minimal downtime, but needs
+additional space to hold the container copy.
++
+When the container is on a local file system and the target storage of
+the backup is an NFS/CIFS server, you should set `--tmpdir` to reside on a
+local file system too, as this will result in a many fold performance
+improvement. Use of a local `tmpdir` is also required if you want to
+backup a local container using ACLs in suspend mode if the backup
+storage is an NFS server.