Re: [atomic-devel] Running docker-storage-setup from a UI

[Vivek Goyal <vgoyal redhat com>]

On Tue, Apr 19, 2016 at 10:32:20AM +0300, Marius Vollmer wrote:

[..]
> > So If I create a partition say /dev/sdb1 and create "mkfs.xfs /dev/sdb1"
> > and later remove partition /dev/sdb1 (which will leave xfs signature
> > somewhere around 2048 sector by default) and then pass disk /dev/sdb
> > to pvcreate, it only complains about dos signature (if it is present). It
> > does not care about if there is any other signature later in the disk.
> 
> Correct.  (But d-s-s will have rejected /dev/sdb already earlier,
> because of the partition table on it.)

Ok, so we have two options.

- If disk the whole disk does not have any signatures, then take ownership
  of disk and don't care about signatures found after creating partitions.

- Always look for signatures and abort operation even if signatures are
  found after creating partition.

Now I am sitting on the fence. Second one seems more safe but at the same
time little hard to use. 

I guess for now, I will implement the first one where we check for
signatures on whole disk and if disk is clean, then take ownership of
it and don't worry about signature on partition.

This will also be consisten with pvcreate behavior where if no signatures
are detected on whole disk, lvm signatures will be created.

Thanks
Vivek