Re: [Qemu-devel] qcow2 - safe on kill? safe on power fail?

[David Barrett]

Anthony Liguori wrote:
> Andreas Schwab wrote:
> > Anthony Liguori <anthony@xxxxxxxxxxxxx> writes:
> >  
> > > The only ways that you can cause corruption is if the QCOW2 sector
> > > allocation code is faulty (and you would be screwed no matter what here)
> > > or if you issue a SIGTERM/SIGKILL that interrupts the code while it's
> > > allocating a new sector.
> >
> > Blocking SIGTERM until the allocation is finished could close that hole.
>
> Seems like a band-aid to me as SIGKILL is still an issue.  Plus it would 
> involve modifying all disk formats, not just QCOW2.  I'd rather see 
> proper journal support added to QCOW2 myself.

Well, SIGKILL is a bit more of an extreme case.  SIGTERM seems like a 
reasonable way to trigger a graceful shutdown (at least, I know I 
assumed it did for a long time, whereas I'd never assume SIGKILL was 
graceful).

-david