* [Qemu-devel] crash with -incoming and -snapshot
@ 2016-02-14 15:52 Paolo Bonzini
2016-02-14 16:12 ` Paolo Bonzini
0 siblings, 1 reply; 5+ messages in thread
From: Paolo Bonzini @ 2016-02-14 15:52 UTC (permalink / raw)
To: qemu-devel
Reproducer:
x86_64-softmmu/qemu-system-x86_64 \
-incoming tcp:localhost:12345 -snapshot \
/vm/virt_test/images/jeos-21-64-base.qcow2
Weird as it may seem, this actually makes some sense for testing
migration with non-shared storage...
Paolo
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [Qemu-devel] crash with -incoming and -snapshot
2016-02-14 15:52 [Qemu-devel] crash with -incoming and -snapshot Paolo Bonzini
@ 2016-02-14 16:12 ` Paolo Bonzini
2016-02-15 9:12 ` [Qemu-devel] [Qemu-block] " Kevin Wolf
0 siblings, 1 reply; 5+ messages in thread
From: Paolo Bonzini @ 2016-02-14 16:12 UTC (permalink / raw)
To: qemu-devel, qemu block
On 14/02/2016 16:52, Paolo Bonzini wrote:
> Reproducer:
>
> x86_64-softmmu/qemu-system-x86_64 \
> -incoming tcp:localhost:12345 -snapshot \
> /vm/virt_test/images/jeos-21-64-base.qcow2
>
>
> Weird as it may seem, this actually makes some sense for testing
> migration with non-shared storage...
In fact, migration with non-shared storage (migrate -b) is broken in
general, even without -snapshot.
Paolo
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [Qemu-devel] [Qemu-block] crash with -incoming and -snapshot
2016-02-14 16:12 ` Paolo Bonzini
@ 2016-02-15 9:12 ` Kevin Wolf
2016-02-15 9:26 ` [Qemu-devel] " Paolo Bonzini
0 siblings, 1 reply; 5+ messages in thread
From: Kevin Wolf @ 2016-02-15 9:12 UTC (permalink / raw)
To: Paolo Bonzini; +Cc: qemu-devel, qemu block
Am 14.02.2016 um 17:12 hat Paolo Bonzini geschrieben:
> On 14/02/2016 16:52, Paolo Bonzini wrote:
> > Reproducer:
> >
> > x86_64-softmmu/qemu-system-x86_64 \
> > -incoming tcp:localhost:12345 -snapshot \
> > /vm/virt_test/images/jeos-21-64-base.qcow2
> >
> >
> > Weird as it may seem, this actually makes some sense for testing
> > migration with non-shared storage...
>
> In fact, migration with non-shared storage (migrate -b) is broken in
> general, even without -snapshot.
Oh cool, does this mean that we can finally remove it? :-)
Kevin
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [Qemu-devel] crash with -incoming and -snapshot
2016-02-15 9:12 ` [Qemu-devel] [Qemu-block] " Kevin Wolf
@ 2016-02-15 9:26 ` Paolo Bonzini
2016-02-15 11:20 ` Kashyap Chamarthy
0 siblings, 1 reply; 5+ messages in thread
From: Paolo Bonzini @ 2016-02-15 9:26 UTC (permalink / raw)
To: Kevin Wolf; +Cc: qemu-devel, qemu block
On 15/02/2016 10:12, Kevin Wolf wrote:
> Am 14.02.2016 um 17:12 hat Paolo Bonzini geschrieben:
>> On 14/02/2016 16:52, Paolo Bonzini wrote:
>>> Reproducer:
>>>
>>> x86_64-softmmu/qemu-system-x86_64 \
>>> -incoming tcp:localhost:12345 -snapshot \
>>> /vm/virt_test/images/jeos-21-64-base.qcow2
>>>
>>>
>>> Weird as it may seem, this actually makes some sense for testing
>>> migration with non-shared storage...
>>
>> In fact, migration with non-shared storage (migrate -b) is broken in
>> general, even without -snapshot.
>
> Oh cool, does this mean that we can finally remove it? :-)
I wouldn't object, but people are using it. :)
Paolo
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [Qemu-devel] crash with -incoming and -snapshot
2016-02-15 9:26 ` [Qemu-devel] " Paolo Bonzini
@ 2016-02-15 11:20 ` Kashyap Chamarthy
0 siblings, 0 replies; 5+ messages in thread
From: Kashyap Chamarthy @ 2016-02-15 11:20 UTC (permalink / raw)
To: Paolo Bonzini; +Cc: Kevin Wolf, qemu-devel, qemu block
On Mon, Feb 15, 2016 at 10:26:17AM +0100, Paolo Bonzini wrote:
>
>
> On 15/02/2016 10:12, Kevin Wolf wrote:
> > Am 14.02.2016 um 17:12 hat Paolo Bonzini geschrieben:
> >> On 14/02/2016 16:52, Paolo Bonzini wrote:
> >>> Reproducer:
> >>>
> >>> x86_64-softmmu/qemu-system-x86_64 \
> >>> -incoming tcp:localhost:12345 -snapshot \
> >>> /vm/virt_test/images/jeos-21-64-base.qcow2
> >>>
> >>>
> >>> Weird as it may seem, this actually makes some sense for testing
> >>> migration with non-shared storage...
> >>
> >> In fact, migration with non-shared storage (migrate -b) is broken in
> >> general, even without -snapshot.
> >
> > Oh cool, does this mean that we can finally remove it? :-)
>
> I wouldn't object, but people are using it. :)
One case I know for sure: Upstream libvirt (consequently, OpenStack
Nova) falls back to 'migrate -b'/("inc:" true) approach when there's no
NBD support on the destination during live block migration:
# From qemuMigrationRun() function in libvirt source
$ less libvirt/src/qemu/qemu_migration.c
[...]
if (migrate_flags & (QEMU_MONITOR_MIGRATE_NON_SHARED_DISK |
QEMU_MONITOR_MIGRATE_NON_SHARED_INC)) {
if (mig->nbd) {
/* This will update migrate_flags on success */
if (qemuMigrationDriveMirror(driver, vm, mig,
spec->dest.host.name,
migrate_speed,
&migrate_flags,
nmigrate_disks,
migrate_disks,
dconn) < 0) {
goto cleanup;
}
} else {
/* Destination doesn't support NBD server.
* Fall back to previous implementation. */
VIR_DEBUG("Destination doesn't support NBD server "
"Falling back to previous implementation.");
}
}
[...]
This fallback also kicks in when people enable TUNNELLED migration (as
NBD does not have support for it in libvirt, due to valid technical
reasons documented else where).
--
/kashyap
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2016-02-15 11:21 UTC | newest]
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2016-02-14 15:52 [Qemu-devel] crash with -incoming and -snapshot Paolo Bonzini
2016-02-14 16:12 ` Paolo Bonzini
2016-02-15 9:12 ` [Qemu-devel] [Qemu-block] " Kevin Wolf
2016-02-15 9:26 ` [Qemu-devel] " Paolo Bonzini
2016-02-15 11:20 ` Kashyap Chamarthy
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