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

[Anthony Liguori]

David Barrett wrote:
> Anthony Liguori wrote:
> > Andreas Schwab wrote:
> > > Anthony Liguori <address@hidden> 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).

It would probably be reasonable to trap SIGTERM and to have it trigger 
the equivalent of the "quit" command in the monitor.  Right now, SIGTERM 
will not result in a graceful shutdown of QEMU.

Regards,

Anthony Liguori

> -david