Re: cgd gives read-only error

[Michael van Elst <mlelstv%serpens.de@localhost>]

On Wed, Jan 09, 2013 at 09:59:19PM -0500, Thor Lancelot Simon wrote:
> On Wed, Jan 09, 2013 at 10:50:57PM +0000, Michael van Elst wrote:
> > prlw1%cam.ac.uk@localhost (Patrick Welche) writes:
> > 
> > >I just tried the "To scrub data from a disk before setting up a cgd"
> > >recipe from cgdconfig on a new amd64 box installed from 12th December 
> > >current dist files. For some reason the dd fails with /dev/rcgd0d
> > >is a read-only file system.
> > 
> > Writing over the disklabel sector (sector 1) gets you the EROFS error.
> > 
> > For "scrubbing a disk before setting a cgd" it doesn't make sense to
> > scrub the disklabel, you should just skip it, or just scrub the
> > partitions.
> 
> None of it makes much sense to me.  Why exactly are we "scrubbing"
> the disk before setting up the cgd?  Just fill the cgd with 0 and
> you are filling the disk with what, really, had darned well better
> look like random data.


Maybe I'm mistaken, but I understood "scrubbing" as dd'ing /dev/zero
to the device, i.e. filling with zeros. The issue was that the raw
partition of cgd cannot be written completely because disk devices
refuse to overwrite the label sector.


Greetings,
-- 
                                Michael van Elst
Internet: mlelstv%serpens.de@localhost
                                "A potential Snark may lurk in every tree."