On 2014年03月05日 23:51, Paulo Vital wrote: > When executing a virsh live migration of a VM created by Kimchi, the > migration stops due to miss configuration "cache=none" on disk's > performance parameters. I'm little worried about make cache 'none' will cause performance downgrade for guest in daily running. Can we allow update this parameter in vm disk edit and change it when we decide to live migrate a vm?

> > Signed-off-by: Paulo Vital <pvital(a)linux.vnet.ibm.com&gt; > --- > src/kimchi/vmtemplate.py | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/src/kimchi/vmtemplate.py b/src/kimchi/vmtemplate.py > index e2d78a4..89b5e72 100644 > --- a/src/kimchi/vmtemplate.py > +++ b/src/kimchi/vmtemplate.py > @@ -152,7 +152,7 @@ class VMTemplate(object): > params = {'src': src, 'dev': dev, 'bus': > self.info['disk_bus']} > ret += """ > <disk type='file' device='disk'> > - <driver name='qemu' type='qcow2'/> > + <driver name='qemu' type='qcow2' cache='none'/> > <source file='%(src)s' /> > <target dev='%(dev)s' bus='%(bus)s' /> > </disk> > @@ -182,7 +182,7 @@ class VMTemplate(object): > # Passthrough configuration > disk_xml = """ > <disk type='volume' device='lun'> > - <driver name='qemu' type='raw'/> > + <driver name='qemu' type='raw' cache='none'/> > <source dev='%(src)s'/> > <target dev='%(dev)s' bus='scsi'/> > </disk>""" _______________________________________________ Kimchi-devel mailing list Kimchi-devel(a)ovirt.org http://lists.ovirt.org/mailman/listinfo/kimchi-devel

On 03/06/2014 08:46 AM, Royce Lv wrote: > On 2014年03月05日 23:51, Paulo Vital wrote: >> When executing a virsh live migration of a VM created by Kimchi, the >> migration stops due to miss configuration "cache=none" on disk's >> performance parameters. > I'm little worried about make cache 'none' will cause performance > downgrade for guest in daily running. > Can we allow update this parameter in vm disk edit and change it when > we decide to live migrate a vm? Agree.

>> >> Signed-off-by: Paulo Vital <pvital(a)linux.vnet.ibm.com&gt; >> --- >> src/kimchi/vmtemplate.py | 4 ++-- >> 1 file changed, 2 insertions(+), 2 deletions(-) >> >> diff --git a/src/kimchi/vmtemplate.py b/src/kimchi/vmtemplate.py >> index e2d78a4..89b5e72 100644 >> --- a/src/kimchi/vmtemplate.py >> +++ b/src/kimchi/vmtemplate.py >> @@ -152,7 +152,7 @@ class VMTemplate(object): >> params = {'src': src, 'dev': dev, 'bus': >> self.info['disk_bus']} >> ret += """ >> <disk type='file' device='disk'> >> - <driver name='qemu' type='qcow2'/> >> + <driver name='qemu' type='qcow2' cache='none'/> >> <source file='%(src)s' /> >> <target dev='%(dev)s' bus='%(bus)s' /> >> </disk> >> @@ -182,7 +182,7 @@ class VMTemplate(object): >> # Passthrough configuration >> disk_xml = """ >> <disk type='volume' device='lun'> >> - <driver name='qemu' type='raw'/> >> + <driver name='qemu' type='raw' cache='none'/> >> <source dev='%(src)s'/> >> <target dev='%(dev)s' bus='scsi'/> >> </disk>""" > > _______________________________________________ > Kimchi-devel mailing list > Kimchi-devel(a)ovirt.org > http://lists.ovirt.org/mailman/listinfo/kimchi-devel

I also worried about that, but I know that the performance team in the past said it was okay, as long as you're running a newer OS: https://ltc3.linux.ibm.com/wiki/LinuxPerformance/KVM-Performance-Tuning We might want to check with the performance team, unless there's a specific case which we know will be impacted by cache=none. Regards, Christy

On Thu, 2014-03-06 at 12:23 -0300, Aline Manera wrote: > On 03/05/2014 11:44 PM, Sheldon wrote: >> On 03/06/2014 08:46 AM, Royce Lv wrote: >>> On 2014年03月05日 23:51, Paulo Vital wrote: >>>> When executing a virsh live migration of a VM created by Kimchi, the >>>> migration stops due to miss configuration "cache=none" on disk's >>>> performance parameters. >>> I'm little worried about make cache 'none' will cause performance >>> downgrade for guest in daily running. >>> Can we allow update this parameter in vm disk edit and change it when >>> we decide to live migrate a vm? >> Agree. > Patches are welcome! =) > >>>> Signed-off-by: Paulo Vital <pvital(a)linux.vnet.ibm.com&gt; >>>> --- >>>> src/kimchi/vmtemplate.py | 4 ++-- >>>> 1 file changed, 2 insertions(+), 2 deletions(-) >>>> >>>> diff --git a/src/kimchi/vmtemplate.py b/src/kimchi/vmtemplate.py >>>> index e2d78a4..89b5e72 100644 >>>> --- a/src/kimchi/vmtemplate.py >>>> +++ b/src/kimchi/vmtemplate.py >>>> @@ -152,7 +152,7 @@ class VMTemplate(object): >>>> params = {'src': src, 'dev': dev, 'bus': >>>> self.info['disk_bus']} >>>> ret += """ >>>> <disk type='file' device='disk'> >>>> - <driver name='qemu' type='qcow2'/> >>>> + <driver name='qemu' type='qcow2' cache='none'/> >>>> <source file='%(src)s' /> >>>> <target dev='%(dev)s' bus='%(bus)s' /> >>>> </disk> >>>> @@ -182,7 +182,7 @@ class VMTemplate(object): >>>> # Passthrough configuration >>>> disk_xml = """ >>>> <disk type='volume' device='lun'> >>>> - <driver name='qemu' type='raw'/> >>>> + <driver name='qemu' type='raw' cache='none'/> >>>> <source dev='%(src)s'/> >>>> <target dev='%(dev)s' bus='scsi'/> >>>> </disk>""" >>> _______________________________________________ >>> Kimchi-devel mailing list >>> Kimchi-devel(a)ovirt.org >>> http://lists.ovirt.org/mailman/listinfo/kimchi-devel >> > _______________________________________________ > Kimchi-devel mailing list > Kimchi-devel(a)ovirt.org > http://lists.ovirt.org/mailman/listinfo/kimchi-devel _______________________________________________ Kimchi-devel mailing list Kimchi-devel(a)ovirt.org http://lists.ovirt.org/mailman/listinfo/kimchi-devel