root disk for instance

Jyoti Dahiwele jyotishri403 at
Thu Jul 11 14:21:04 UTC 2019

Thanks for your reply.
I'm referring this link
to understand about root disk. In this it is saying root disk will come
from compute node. What is the location of root disk on compute node?

If I want to keep all my vms on shared storage . How to configure it ?

Or If I want to keep all my vms on cinder volume. What will be the
configuration for it on nova and cinder?

On Thu, 11 Jul 2019, 15:24 Eugen Block, <eblock at> wrote:

> Hi,
> it's always glance that serves the images, it just depends on how you
> decide to create the instance, ephemeral or persistent disks. You can
> find more information about storage concepts in [1].
> If I'm not completely wrong, since Newton release the default in the
> Horizon settings is to create an instance from volume, so it would be
> a persistent disk managed by cinder (the volume persists after the
> instance has been deleted, this is also configurable). The image is
> downloaded from glance into a volume on your volume server.
> If you change the Horizon behavior or if you launch an instance from
> the cli you'd get an ephemeral disk by nova, depending on your storage
> backend this would be a local copy of the image on the compute node(s)
> or something related in your storage backend, e.g. an rbd object in
> ceph.
> Does this clear it up a bit?
> Regards,
> Eugen
> [1]
> Zitat von Jyoti Dahiwele <jyotishri403 at>:
> > Dear Team,
> >
> > Please clear me my following doubts.
> > When I use image from source option  and mini flavor to create an
> instace,
> > from which storage pool instance will get root disk ? From cinder or
> glance?
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