[libvirt] [PATCH] set cache=off on -disk line in qemu driver if <shareable/> (but not <readonly/>) is set.

[Daniel P. Berrange]

On Mon, Nov 03, 2008 at 06:37:45PM +0200, Dor Laor wrote:
> Daniel Veillard wrote:
> >On Sat, Nov 01, 2008 at 06:20:27PM -0500, Charles Duffy wrote:
> >  
> >>As cache=off is necessary for clustering filesystems such as GFS (and  
> >>such is the point of shareable, yes?), I believe this is correct 
> >>behavior.
> >>
> >>Comments?
> >>    
> >
> >  Yes that sounds right, if shared over network we should not cache
> >locally in the OS,
> >
> >    applied and commited,
> >
> >      thanks !
> >
> >Daniel
> cache=off should be the default case (or the similar O_DSYNC case).
> cache=on should only be used for temporal usage and not really 
> production data.
> It's just unsafe to use caching if you data is important to you.
> It's a hot issue in the qemu mailing list.

I was under the impression its already been solved on qemu mailing list.
AFAIK, they changed the defalt option to ensure data safety upon host
crash, so we have no need to set any cache= option by default.

Daniel
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