Re: Snapshot/Rollback using LVM/EVMS
"email@example.com" <firstname.lastname@example.org> writes:
> I am using debian linux and i want to make a system snapshot using LVM
> or EVMS.
> Now i am having running system with one partition (/dev/hda1 of 30GB,
> ~7GB used) and i can't modify or delete existing data.
> I want to take the snapshot (one or more) in some point, save it
> locally and rollback if needed.
> My question is what better to use LVM or EVMS?
Lvm snapshots only works on lvm logical volumes. So no luck with your
/dev/hda1. Evms on the other hand can work directly with normal
partitions in some ways. Check for details.
Also you can't realy rollback with lvm snapshots. When you do a
snapshot you create a copy (on write) of the volume. If you change the
original volume (and that is still the mounted system) that volume
remains changed while the snapshot gets a copy of the original data.
To rollback you would have to reboot and use the snapshot device as
Alternatively you can reboot using the snapshot device before any
alterations. A rollback is then just a reboot with the old device.
As of now there is also now "commit" tool to merge the changes stored
in a snapshot back into the original device. Rollback and commiting a
snapshot is toaly possible with lvm (with an umounted FS on the devcie
you overwrite), there just isn't a frontend for it.
> What exact steps to make system snapshot and rollback with both of
> Note: I have the User Guide of both of them, but it a little confusing.