openstack team mailing list archive

[Yuriy Taraday <yorik.sar@xxxxxxxxx>]

Fill-first cost function returns the amount of free RAM. By default it
is negated (multiplied by -1.0), so the less free RAM is better.

I think, this is a bit misguiding, but was changed right before Essex
(see https://bugs.launchpad.net/nova/+bug/965732 ).

Kind regards, Yuriy.


On Thu, May 3, 2012 at 8:05 PM, Lorin Hochstein
<lorin@xxxxxxxxxxxxxxxxxx> wrote:
> Yuriy:
>
>
> On May 3, 2012, at 4:46 AM, Yuriy Taraday wrote:
>
> Just note that since Essex release Nova by default use fill-first cost
> function, meaning that nodes with less free RAM will be preferred for
> new instances.
>
> Kind regards, Yuriy.
>
>
> I thought the default behavior in essex was spread-first:
>
> From:
>
> https://github.com/openstack/nova/blob/stable/essex/nova/scheduler/least_cost.py#L41
>
>     cfg.FloatOpt('compute_fill_first_cost_fn_weight',
>              default=-1.0,
>                help='How much weight to give the fill-first cost function. '
>                     'A negative value will reverse behavior: '
>                     'e.g. spread-first'),
>     ]
>
>
>
>
> Take care,
>
> Lorin
> --
> Lorin Hochstein
> Lead Architect - Cloud Services
> Nimbis Services, Inc.
> www.nimbisservices.com
>
>