Re: [Libvir] PATCH: 12/16: logical volume backend

On Tue, Feb 19, 2008 at 03:43:11AM -0500, Daniel Veillard wrote: > > + > > + /* > > + * LVM requires that the first 512 bytes are blanked if using > > + * a whole disk as a PV. So we just blank them out regardless > > + * rather than trying to figure out if we're a disk or partition > > + */ > > is it really 512 or the block size on the device used ? But 512 is > probably sufficient for LVM to consider it cleared, just wondering ... The 'pvcreate' man page explicitly says the first sector <quote> For whole disk devices only the partition table must be erased, which will effectively destroy all data on that disk. This can be done by zeroing the first sector with: dd if=/dev/zero of=PhysicalVolume bs=512 count=1 </quote> So 512 is fine for MSDOS partition tables at least.