Re: [Qemu-devel] Re: [PATCH] virtio-blk: assign a default serial number if none provided

[Ryan Harper]

* Michael S. Tsirkin <address@hidden> [2010-06-02 04:08]:
> On Tue, Jun 01, 2010 at 08:48:54PM -0500, Ryan Harper wrote:
> > This patch applies on-top of John's virtio-blk serial patches.
> > 
> > Generate default serial numbers for virtio drives based on DriveInfo.unit 
> > which is
> > incremented for each additional virtio-blk device.  This provides a
> > per-virtio-blk number to use in the default string: QM%05d that is used in
> > hw/ide/core.c.  The resulting serial number looks like: QM00001, etc.
> > 
> > Signed-off-by: Ryan Harper <address@hidden>
> 
> 
> I think that there's a problem with this approach in that hot plug A,
> hot plug B, hot unplug A is not the same as hot plug B.
> So you might get guest boot failures and no easy way to
> figure out why. For guests that need S/N, I think they
> really must be persistent.

That's true; though I think most boot drives boot via either LVM or UUID
which will remain persistent.  That said, if you are relying on the
by-id; then of course the user will need to specify serial versus having
one auto-generated.

-- 
Ryan Harper
Software Engineer; Linux Technology Center
IBM Corp., Austin, Tx
address@hidden