[ovirt-users] Spam Cluster Polcies

[Gilad Chaplik]

----- Original Message -----
> From: "Jiri Moskovcak" <jmoskovc at redhat.com>
> To: "Gilad Chaplik" <gchaplik at redhat.com>, "Maurice James" <mjames at media-node.com>
> Cc: "users" <users at ovirt.org>
> Sent: Monday, June 30, 2014 3:57:29 PM
> Subject: Re: [ovirt-users] Spam  Cluster Polcies
> 
> On 06/30/2014 01:53 PM, Gilad Chaplik wrote:
> > ----- Original Message -----
> >> From: "Maurice James" <mjames at media-node.com>
> >> To: "users" <users at ovirt.org>
> >> Sent: Friday, June 27, 2014 1:20:23 AM
> >> Subject: [ovirt-users] Spam  Cluster Polcies
> >>
> >> Can someone explain the cluster policies to me? The explanation at
> >> http://www.ovirt.org/Features/Even_VM_Count_Distribution is not quite
> >> clicking for me.
> >>
> >>
> >>
> >>      * HighVMSCount - Maximum VM limit. Exceeding it qualifies the host as
> >>      overloaded. ( Understood )
> >
> > minimal #vms on host to enable the module (i.e worst host should have more
> > than HighVMSCount vms).
> >
> >>      * MigrationThreshold - defines a buffer before we start migrating VMs
> >>      from the host ( Not quite grasping. If my High limit is 5 does this
> >>      mean
> >>      that it will only begin to move VMs when the count reaches 10? )
> >
> > don't think that there's any relation with "HighLimit".
> > It means that migration will happen only if there is a difference of X vms
> > or more between worst host (source host) to destination host.
> >
> > let say that you have 2 hosts. one has 10 vms and the second 8. if the
> > threshold is 3, no migration will happen (10-8 !> 3).
> 
> - exactly
> 
> >
> >>      * SPMVMCountGrace - defines how many slots for VMs should be reserved
> >>      on
> >>      SPM hosts (the SPM host should have less load than others, so this
> >>      variable defines how many VM less it should have) ( Does this mean
> >>      that
> >>      if I have a host with only 3 VMs the SPM will 3 VMs minus the
> >>      SpmWmGrace? Or is this HighVmCount minus SpmVmGrace count?)
> >
> > you're right, the SPM host will have current + grace VMs in terms of module
> > calculations.
> > I think that this is problematic, it is likely to be selected as worst host
> > candidate and that's not the wanted behavior iiuc
> > imo, we should subtract (-) in overloaded hosts and add (+) in
> > underutilized.
> 
> - I think it's correct as it is, if the SpmVmGrace+currentVms >
> HighVmCount it is overutilized and should be freed if possible.

not sure I understand, let's take an example
2 hosts: spm: 8 #vms, hsm: 8 #vms. 
SPMVMCountGrace = 2.
in this case the 'worst' host will be the SPM... shouldn't we deduct 2 from spm and not add? we want less noise there.

> 
> --J
> 
> >
> > @Jirka?
> >
> >>
> >>
> >>
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> >> http://lists.ovirt.org/mailman/listinfo/users
> >>
> 
>