On Wed, Mar 25, 2020 at 04:40:48PM +0100, Dietmar Maurer wrote:
> > On March 25, 2020 1:39 PM Sergio Lopez <slp@redhat.com> wrote:
> > 
> >  
> > On Wed, Mar 25, 2020 at 01:29:48PM +0100, Dietmar Maurer wrote:
> > > > As expected, if both BDS are running on the same IOThread (and thus,
> > > > the same AioContext), the problem is not reproducible.
> > > >
> > > > In a general sense, we could say that completion modes other than
> > > > "individual" are not supported for a transaction that may access
> > > > different AioContexts. I don't see a safe an easy way to fix this. We
> > > > could opt for simply detect and forbid such completion modes when the
> > > > BDS's are assigned to different AioContexts. Perhaps Kevin (in CC) has
> > > > a better idea.
> > >
> > > So the solution is to disable backups when using io-threads?
> > >
> > 
> > I meant forbidding transactions with completion-mode == grouped. It
> > would be still possible running transactions (and thus, backups) with
> > completion-mode == individual, which is the default.
> 
> As mentioned earlier, even a totally simple/normal backup job fails when
> using io-threads and the VM is under load. It results in a total
> VM freeze!
> 

This is definitely a different issue. I'll take a look at it today.

Cheers,
Sergio.