[Maas-devel] Which disk is the root disk (Juju + MAAS)

[Mark Shuttleworth]

On 30/07/14 15:56, Scott Moser wrote:
> curtin probably did install to what it thought was the first disk.  2
> things then are possible from there:
>  a.) disks came up in a different order on reboot, but the LABEL=
>      successfully did find the root disk, which is good.
>  b.) disks came up in the same order, but existing LABEL of
>      cloudimg-rootfs and *its* undefined order made root be /dev/sdb.
>      I dont suspect this, though as it would have resulted in bad juju
>      user-data, and probably fail to boot.
>
> So it surely would have seemed like 'a'.  I'm not sure exactly what we can
> do about that.
>
> There are definitely ways of finding devices by a more consistent path.
> Ie, you can use /dev/disk/by-lable or /dev/disk/by-uuid, but i don't know
> that you can easily guarantee that a given block device (possibly by its
> path) will be /dev/sda and another will be /dev/sdb.

Is there no equivalent to /etc/udev/rules.d/70-persistent-net.rules for
disks?

> Certainly the charm can be made more generic to find an "empty" device
> rather than picking /dev/sdb.

Right, because in some cases the system might well have been placed on
sdb deliberately.

Mark

-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 246 bytes
Desc: OpenPGP digital signature
URL: <https://lists.ubuntu.com/archives/maas-devel/attachments/20140730/21881149/attachment.pgp>