10:14 a.m.
I was interested in using 'virsh vol-upload' and 'virsh vol-download',
rather than mucking about directly with the filesystem. But while
simply copying the image is relatively quick:
# ls -l /var/lib/libvirt/images/centos-7-cloud.qcow2
-rw-r--r--. 1 qemu qemu 1004994560 Apr 15 2015 centos-7-cloud.qcow2
# time cp /var/lib/libvirt/images/centos-7-cloud.qcow2 /tmp/myimage.qcow2
real 0m10.829s
user 0m0.024s
sys 0m1.668s
Trying to do the same thing with `virsh vol-download` is glacial:
# time virsh vol-download --pool default centos-7-cloud.qcow2 /tmp/myimage.qcow2
I killed it after 10 minutes:
real 10m20.775s
user 10m19.451s
sys 0m1.887s
After which is was about halfway through:
# ls -l /tmp/myimage.qcow2
-rw-r--r--. 1 root root 564920248 Mar 4 11:11 /tmp/myimage.qcow2
What is up with that?
--
Lars Kellogg-Stedman <lars(a)redhat.com> | larsks @ {freenode,twitter,github}
Cloud Engineering / OpenStack | http://blog.oddbit.com/
10:57 a.m.
On Fri, Mar 04, 2016 at 11:14:44AM -0500, Lars Kellogg-Stedman wrote:
I was interested in using 'virsh vol-upload' and 'virsh
vol-download',
rather than mucking about directly with the filesystem. But while
simply copying the image is relatively quick:
# ls -l /var/lib/libvirt/images/centos-7-cloud.qcow2
-rw-r--r--. 1 qemu qemu 1004994560 Apr 15 2015 centos-7-cloud.qcow2
# time cp /var/lib/libvirt/images/centos-7-cloud.qcow2 /tmp/myimage.qcow2
real 0m10.829s
user 0m0.024s
sys 0m1.668s
Trying to do the same thing with `virsh vol-download` is glacial:
# time virsh vol-download --pool default centos-7-cloud.qcow2 /tmp/myimage.qcow2
I killed it after 10 minutes:
real 10m20.775s
user 10m19.451s
sys 0m1.887s
After which is was about halfway through:
# ls -l /tmp/myimage.qcow2
-rw-r--r--. 1 root root 564920248 Mar 4 11:11 /tmp/myimage.qcow2
What is up with that?
What version of libvirt ? We had an unfortunate implementation mistake
which caused us to waste tonnes of time in memmove(). versions since
1.2.19 have a fix that addresses it
commit d9c9e138f22c48626f719f880920e04c639e0177
Author: Ossi Herrala <oherrala(a)gmail.com>
Date: Mon Jul 20 12:44:32 2015 +0000
rpc: Fix slow volume download (virsh vol-download)
Use I/O vector (iovec) instead of one huge memory buffer as suggested
in https://bugzilla.redhat.com/show_bug.cgi?id=1026137#c7. This avoids
doing memmove() to big buffers and performance doesn't degrade if
source (virNetClientStreamQueuePacket()) is faster than sink
(virNetClientStreamRecvPacket()).
Resolves: http://bugzilla.redhat.com/1026137
Signed-off-by: Martin Kletzander <mkletzan(a)redhat.com>
Regards,
Daniel
--
|: http://berrange.com -o- http://www.flickr.com/photos/dberrange/ :|
|: http://libvirt.org -o- http://virt-manager.org :|
|: http://autobuild.org -o- http://search.cpan.org/~danberr/ :|
|: http://entangle-photo.org -o- http://live.gnome.org/gtk-vnc :|
11:09 a.m.
On Fri, Mar 04, 2016 at 04:57:30PM +0000, Daniel P. Berrange wrote:
What version of libvirt ? We had an unfortunate implementation
mistake
which caused us to waste tonnes of time in memmove(). versions since
1.2.19 have a fix that addresses it
Ah, this is on F23, which has:
libvirt-1.2.18.2-2.fc23.x86_64
There's nothing more recent right now in either updates or
updates-testing (and I was hoping to target (RHEL/CentOS)7, which have
libvirt-1.2.17-13.el7_2.2.x86_64).
Thanks,
--
Lars Kellogg-Stedman <lars(a)redhat.com> | larsks @ {freenode,twitter,github}
Cloud Engineering / OpenStack | http://blog.oddbit.com/
11:21 a.m.
On Fri, Mar 04, 2016 at 12:09:55PM -0500, Lars Kellogg-Stedman wrote:
On Fri, Mar 04, 2016 at 04:57:30PM +0000, Daniel P. Berrange wrote:
> What version of libvirt ? We had an unfortunate implementation mistake
> which caused us to waste tonnes of time in memmove(). versions since
> 1.2.19 have a fix that addresses it
Ah, this is on F23, which has:
libvirt-1.2.18.2-2.fc23.x86_64
There's nothing more recent right now in either updates or
updates-testing (and I was hoping to target (RHEL/CentOS)7, which have
libvirt-1.2.17-13.el7_2.2.x86_64).
You can checkout virt-preview if you want to try out newer versions
https://fedorapeople.org/groups/virt/virt-preview/
Regards,
Daniel
--
|: http://berrange.com -o- http://www.flickr.com/photos/dberrange/ :|
|: http://libvirt.org -o- http://virt-manager.org :|
|: http://autobuild.org -o- http://search.cpan.org/~danberr/ :|
|: http://entangle-photo.org -o- http://live.gnome.org/gtk-vnc :|
11:35 a.m.
On Fri, Mar 04, 2016 at 05:21:27PM +0000, Daniel P. Berrange wrote:
You can checkout virt-preview if you want to try out newer versions
https://fedorapeople.org/groups/virt/virt-preview/
Well, that certainly solves my problem with vol-download :). Do you
know if that fix is likely to show up in EL7?
--
Lars Kellogg-Stedman <lars(a)redhat.com> | larsks @ {freenode,twitter,github}
Cloud Engineering / OpenStack | http://blog.oddbit.com/
11:55 a.m.
On Fri, Mar 04, 2016 at 12:35:22PM -0500, Lars Kellogg-Stedman wrote:
On Fri, Mar 04, 2016 at 05:21:27PM +0000, Daniel P. Berrange wrote:
> You can checkout virt-preview if you want to try out newer versions
>
> https://fedorapeople.org/groups/virt/virt-preview/
Well, that certainly solves my problem with vol-download :). Do you
know if that fix is likely to show up in EL7?
It'll be fixed in 7.3 since that'll pull a new libvirt.
Regards,
Daniel
--
|: http://berrange.com -o- http://www.flickr.com/photos/dberrange/ :|
|: http://libvirt.org -o- http://virt-manager.org :|
|: http://autobuild.org -o- http://search.cpan.org/~danberr/ :|
|: http://entangle-photo.org -o- http://live.gnome.org/gtk-vnc :|
3150
days inactive
3150
days old
5 comments
2 participants
participants (2)
-
Daniel P. Berrange -
Lars Kellogg-Stedman