[ovirt-users] Spam Cluster Polcies

[Gilad Chaplik]

----- 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).

>     * 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.

@Jirka?

> 
> 
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