fsfreeze is unnecessary for device-mapper devices. The device-mapper (and
LVM) automatically freezes a filesystem on the device when a snapshot
creation is requested. For more details see the dmsetup(8) man page. -c Indicates that added identities should be subject to confirmation be‐
fore being used for authentication. Confirmation is performed by
ssh-askpass(1). Successful confirmation is signaled by a zero exit
status from ssh-askpass(1), rather than text entered into the re‐
quester.
I'm a bit surprised that this is not mention in the article, as this seems very useful to make exploits more difficult.
I guess MS-SQL does something similar, and that does seem useful beyond what LVM does.
Also VSS apparently can offload the snapshotting to a SAN ('VSS Hardware Provider'): https://docs.microsoft.com/en-us/windows-server/storage/file...