Open Stack

On Fri, 5 Aug 2022 at 11:51, Gorka Eguileor <geguileo at redhat.com> wrote:
>
> On 05/08, Ignazio Cassano wrote:
> > Migrating again to a new node (COMPUTE C) it takes 10 sec.
> > The first migration from A to B (750 sec)  is slow in migrating memory :
> >
> >
> > *migration running for 30 secs, memory 89% remaining; (bytes
> > processed=1258508063, remaining=15356194816, total=17184923648)2022-08-05
> > 10:47:23.910 55600 INFO nova.virt.libvirt.driver
> > [req-ff02667e-9d38-4a08-9c63-013ed1064218 66adb965bef64eaaab2af93ade87e2ca
> > 85cace94dcc7484c85ff9337eb1d0c4c - default default] [instance:
> > d1aae4bb-9a2b-454f-9018-568af6a98cc3] Migration running for 60 secs, memory
> > 87% remaining; (bytes processed=1489083638, remaining=15035801600,
> > total=17184923648)08-9c63-013ed1064218 66adb965bef64eaaab2af93ade87e2ca
> > 85cace94dcc7484c85ff9337eb1d0c4c - default default] [instance:
> > d1aae4bb-9a2b-454f-9018-568af6a98cc3] Migration running for 90 secs, memory
> > 86% remaining; (bytes processed=1689004421, remaining=14802731008,
> > total=17184923648)*
> >
> > and so on
>
> That sounds crazy to me.  Unless the first node has more load or more
> network usage than the others, or the VM isn't actually running on
> Compute B so the migration is not really of a running VM...

Wow, I agree it looks crazy just like Gorka has said. Indeed, by
looking at the counters, it seems the process is progressing at
approx. the rate of 1.4 GB per minute so approx. 12 minutes total
makes perfect sense.
So it really boils down to "why is the memory migration so slow?".
More like a topic to discuss with libvirt, QEMU and KVM folks as I
doubt nova (and the rest of the OpenStack stuff) has any impact on it.

-yoctozepto