On Mon, 2010-06-14 at 06:49 -0400, Jeremy Fitzhardinge wrote:
> On 06/11/2010 07:11 PM, Neobiker wrote:
> > Hi
> >
> > Valtteri Kiviniemi-2 wrote:
> >
> >> Hi, Ah, misunderstanding sorry, you were talking about disk images :)
> >>
> >>
> > I'm talking about this config:
> > disk = [
> > 'phy:/dev/vm/vm01,xvda1,w',
> > 'phy:/dev/vm/vm01-swap,xvda2,w',
> > 'phy:/dev/daten/devel_debian_amd64,xvda3,w',
> > ]
> >
>
> file: is definitely unsafe; its IO gets buffered in the dom0 pagecache,
> which means the guests writes aren't really writes. I believe phy: has
> similar problems, whereas tap:aio: implemented direct IO. But someone
> more storagey can confirm.
Unless there's a difference in type names between XCP and .org, 'phy'
means a bare LUN plugged into blkback?
Those run underneath the entire block cache subsystems, which ironically
has caching issues of it's own.
But your writes are safe.
Daniel
_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel
|
Home