I asked a colleague about this a while back but was met with a no answer, answer. I have searched on the internet but all I get is a bunch of irrelevant technical information which provides a no answer, answer. ... 6 months has passed and I still feel I do not know the answer to this question. During the usual backup cycle we turn off each VM instance to create a 1:1 copy of the machine and its residing directory. Once the backup is complete the machine gets switched back on. No big deal, it doesn't really take long at all. What I have always wondered though, is can the VMs be copied and backed up while they're running, without any threat to the integrity of the data of either the original or backup?