[Qemu-devel] Re: [et-mgmt-tools] Image Corruption Possible with qemu and qemu-kvm

[Sven Oehme]

qemu-devel-bounces+oehmes=de.ibm.com at nongnu.org wrote on 08/28/2007 
04:13:02 AM:

> Anthony Liguori wrote:
> >> In the scenario you mention, libvirt should probably do a sanity 
check for
> >> this before letting you start the guest. libvirt already supports the 
idea
> >> of 'shared' disk images where two or more guests can be 
> optionally configured 
> >> to have write access - basically assumes the admin requesting sharing 
knows
> >> what they're doing.
> >> 
> >
> > I think this is the right level myself.  Advisory locks work okay but
> > not all filesystems support them.  It's particularly nasty when you 
have
> > a clustered filesystem in the host.  I think it would do more harm 
than
> > good to have a feature like that was supposed to provide a safe-guard
> > but then frequently didn't work.
> > 
> 
> There's still the unmanaged use case to worry about.  I think qemu can 
> default to advisory locking, and management tools can do their own 
> locking and always override qemu.
> 
> It's too easy to kill an image by starting up another instance right 
now.
> 

i agree default should be advisory locking and a switch to disable it ..
would that be hard to implement ?

thanks. Sven
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