Open Stack

On Sat, May 18, 2013 at 4:14 PM, Duncan Thomas <duncan.thomas at gmail.com>wrote:

> On 15 May 2013 06:22, John Griffith <john.griffith at solidfire.com> wrote:
>
> > What I had in mind for Cinder, was the addition of of a property/column
> in
> > the Volume object.  This would be a Read Only flag.  The use case here
> would
> > be that a tenant could take a volume that they've populated with data and
> > set it to R/O explicitly.  This would mean providing an API call to
> enabled
> > setting and clearing of this flag of course.
>
> This seems like a useful feature
>
> > In addition, I'd like to modify the cinder attach code, so that if for
> > example a volume is "in use" attached to an instance, and a subsequent
> > attach was requested, rather than failing stating that the volume must be
> > available, we allow the attach however set it as Read Only.  This would
> be
> > the default behavior, if we get to a point where we are interested in
> > multiple attach R/W (which is quite frankly rather scary to me) I would
> > propose that there explicit settings a user must request to do this and
> that
> > it's done via extension or disabled by default via the cinder.conf file.
>
> I think that doing a read-only attach rather than failing the attach
> by default is a /really/ bad idea... for most filesystems, that mount
> is going to be entirely useless if there is a R/W mount in existance,
> and it is going to lead to read corruption in surprising ways. The
> current behaviour is far in preference to that.
>
> Any form of multi-attach should only happen if specifically requested,
> and come with 'here be dragons' warnings...
>
> I agree, probably not such a hot idea to try and have it as default
behavior.

>
> --
> Duncan Thomas
>
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