[ovirt-users] Re: High performance VM cannot migrate due to TSC frequency
Gianluca Cecchi <gianluca.cecchi(a)gmail.com> writes:
Hello,
I'm in 4.4.3 and CentOS 8.3 with 3 hosts.
I have a high performance VM that is running on ov300 and is configured to
be run on any host.
It seems that both if I set or not the option
Migrate only to hosts with the same TSC frequency
I always am unable to migrate the VM and inside engine.log I see this:
2020-12-11 15:56:03,424+01 INFO
[org.ovirt.engine.core.bll.scheduling.SchedulingManager] (default task-36)
[e4801b28-c832-4474-aa53-4ebfd7c6e2d0] Candidate host 'ov301'
('382bfc8f-60d5-4e06-8571-7dae1700574d') was filtered out by
'VAR__FILTERTYPE__INTERNAL' filter 'Migration-Tsc-Frequency'
(correlation
id: null)
2020-12-11 15:56:03,424+01 INFO
[org.ovirt.engine.core.bll.scheduling.SchedulingManager] (default task-36)
[e4801b28-c832-4474-aa53-4ebfd7c6e2d0] Candidate host 'ov200'
('949d0087-2c24-4759-8427-f9eade1dd2cc') was filtered out by
'VAR__FILTERTYPE__INTERNAL' filter 'Migration-Tsc-Frequency'
(correlation
id: null)
Can you verify if it is only my problem?
Apart from the problem itself, what is "TSC frequency" and how can I check
if my 3 hosts are different or not indeed?
TSC frequency is the frequency with which Time Stamp Counter register is
updated, typically a nominal CPU frequency (see
https://en.wikipedia.org/wiki/Time_Stamp_Counter for more details).
You can check the value oVirt gets from libvirt by running
# virsh -r capabilities
and looking at the line like
<counter name='tsc' frequency='2133409000' scaling='no'/>
in the output. Unless frequency scaling is available, the host
frequencies must be almost the same in order to be able to migrate high
performance VMs among them.
Note there is a bug that may cause a migration failure for the VMs even
between hosts with the same frequencies
(https://bugzilla.redhat.com/1821199). But this is apparently not your
case, since the migration is prevented already by Engine.
Regards,
Milan
Normal VMs are able to migrate without problems
Thanks,
Gianluca
_______________________________________________
Users mailing list -- users(a)ovirt.org
To unsubscribe send an email to users-leave(a)ovirt.org
Privacy Statement: https://www.ovirt.org/privacy-policy.html
oVirt Code of Conduct: https://www.ovirt.org/community/about/community-guidelines/
List Archives:
https://lists.ovirt.org/archives/list/users@ovirt.org/message/2HYSCVHSVZS...