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

[Dor Laor <dlaor redhat com>]

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.

Cheers,
Dor