How reliable is the ZFS snapshot if I make it during file operation?
I ask it because I would like to upgrade my XEN Hypervisor from 13.1 to 13.2 ( hypervisor use zfs and provides dataset to guests which have UFS) but before upgrade I want to replicate the guest datasets if something goes wrong.
I successfully upgraded guests some days ago to 13.2 and snapshot saved my life and I did it on the live system (means that the guest was running when I released snapshot command its dataset).
But this implied a question for me: how reliable to do snapshot on a live system? What happen if I release this command during a file write?
For example the guest OS start to write a big file (more blocks) and when I release snapshot command only block1 is written from this point any future writes will not be a part of the snapshot won't it?
I ask it because I would like to upgrade my XEN Hypervisor from 13.1 to 13.2 ( hypervisor use zfs and provides dataset to guests which have UFS) but before upgrade I want to replicate the guest datasets if something goes wrong.
I successfully upgraded guests some days ago to 13.2 and snapshot saved my life and I did it on the live system (means that the guest was running when I released snapshot command its dataset).
But this implied a question for me: how reliable to do snapshot on a live system? What happen if I release this command during a file write?
For example the guest OS start to write a big file (more blocks) and when I release snapshot command only block1 is written from this point any future writes will not be a part of the snapshot won't it?