On Thu, Feb 6, 2014 at 11:01 AM, Dennis Jacobfeuerborn <dennisml at conversis.de> wrote: > On 06.02.2014 11:45, C. L. Martinez wrote: >> Hi all, >> >> I have a strange problem when I use lvm disks to expose to virtual >> guests (host is CentOS 6.5 x86_64). If I remove a kvm guest and all >> lvm disks attached to it, and I create a new kvm with another lvm >> disks that use the same disk space previously assigned to the previous >> kvm guest, this new guest sees all partitions and data. Creating new >> lvm volumes with different names to this new kvm doesn't resolves the >> problem. >> >> Any idea why?? > > When you delete a volume the data isn't cleared only the metadata > removed so if you later create a new volume that ends up using the same > area on disk then you will see the old data as expected. > If you don't want this to happen then you need to overwrite the volume > before you delete it. > > This is a general issue in virtualization/clouds that you need to take > into account for security reasons. See for example: > https://github.com/fog/fog/issues/2525 > > Regards, > Dennis Many thanks Dennis ... Then if I do: dd if=/dev/zero of=/dev/sdc1 bs=1M (it is a 1TiB disk), will erase all data and partitions created by the kvm guest??