Re: [Kimchi-devel] [PATCH] bug fix: setup disks to use cache=none to support live migration.

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