Re: [ovirt-users] Spam Cluster Polcies

----- Original Message ----- > From: "Jiri Moskovcak" <jmoskovc(a)redhat.com&gt; > To: "Gilad Chaplik" <gchaplik(a)redhat.com&gt;, "Maurice James" <mjames(a)media-node.com&gt; > Cc: "users" <users(a)ovirt.org&gt; > 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(a)media-node.com&gt; >>> To: "users" <users(a)ovirt.org&gt; >>> 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? >> >>> >>> >>> >>> _______________________________________________ >>> Users mailing list >>> Users(a)ovirt.org >>> http://lists.ovirt.org/mailman/listinfo/users >>> > >