maas-devel team mailing list archive

[Mark Shuttleworth <mark@xxxxxxxxxx>]

Interesting - at this stage I don't think we're modelling storage in
MAAS, so I would have thought the choice of root disk was entirely done
by curtin. Scott M cc'd for curtin commentary.

It *might be* that:

 * curtin comes up on the machine and picks /dev/sda
 * it writes an fstab with the UUID of that disk (not "/dev/sda"), e.g.

$ cat /etc/fstab
LABEL=cloudimg-rootfs / ext4 defaults 0 0

   - it does not write anything which explicitly maps that UUID to sda

 * the machine reboots
 * in this case whatever assigns disk device names sees a different disk
first, becoming sda, and the labelled disk second, which it marks as sdb

Either way the charm should *handle* an sdb root disk, but yes, we
shouldn't move disks around like that unexpectedly.

Mark


On 30/07/14 15:13, David Britton wrote:
> Hi MAASers --
>
> I deployed a charm yesterday (swift-storage) to Juju + MAAS, and the
> disk obtained for root was '/dev/sdb', which caused an issue in the
> swift-storage charm:
>
> https://bugs.launchpad.net/charms/+source/swift-storage/+bug/1350049
> https://bugs.launchpad.net/charms/+source/swift-storage/+bug/1350051
>
> I searched around for any contract inherent in Juju+MAAS and couldn't
> find one.
>
> Is it expected that /dev/sda will be the root disk?  Was this case I had
> a valid bug?
>

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