From: Dietmar Maurer <dietmar@proxmox.com>
To: Sergio Lopez <slp@redhat.com>
Cc: kwolf@redhat.com, "jsnow@redhat.com" <jsnow@redhat.com>,
"qemu-devel@nongnu.org" <qemu-devel@nongnu.org>,
Stefan Hajnoczi <stefanha@redhat.com>,
Max Reitz <mreitz@redhat.com>
Subject: Re: backup transaction with io-thread core dumps
Date: Wed, 25 Mar 2020 16:40:48 +0100 (CET) [thread overview]
Message-ID: <1427176168.41.1585150848553@webmail.proxmox.com> (raw)
In-Reply-To: <20200325123905.4mygg2ljie7prtbc@dritchie>
> 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!
next prev parent reply other threads:[~2020-03-25 15:41 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-24 11:13 backup transaction with io-thread core dumps Dietmar Maurer
2020-03-24 13:30 ` Dietmar Maurer
2020-03-24 13:33 ` Dietmar Maurer
2020-03-24 13:44 ` John Snow
2020-03-24 14:00 ` Dietmar Maurer
2020-03-24 13:47 ` Max Reitz
2020-03-24 14:02 ` Dietmar Maurer
2020-03-24 16:49 ` Dietmar Maurer
2020-03-25 11:40 ` Stefan Reiter
2020-03-25 12:23 ` Vladimir Sementsov-Ogievskiy
2020-03-25 15:50 ` [PATCH] backup: don't acquire aio_context in backup_clean Stefan Reiter
2020-03-26 5:54 ` Vladimir Sementsov-Ogievskiy
2020-03-26 9:43 ` Stefan Reiter
2020-03-26 12:46 ` Vladimir Sementsov-Ogievskiy
2020-03-26 11:53 ` Sergio Lopez
2020-03-25 8:13 ` backup transaction with io-thread core dumps Sergio Lopez
2020-03-25 11:46 ` Sergio Lopez
2020-03-25 12:29 ` Dietmar Maurer
2020-03-25 12:39 ` Sergio Lopez
2020-03-25 15:40 ` Dietmar Maurer [this message]
2020-03-26 7:50 ` Sergio Lopez
2020-03-26 8:14 ` Dietmar Maurer
2020-03-26 9:23 ` Dietmar Maurer
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