Re: [ckrm-tech] [PATCH] BC: resource beancounters (v4) (added user memory)

[Pavel Emelianov <xemul@openvz.org>]

Balbir Singh wrote:
> Pavel Emelianov wrote:
> <snip>
>
>>>>>> E.g. I have a node with 1Gb of ram and 10 containers with 100Mb
>>>>>> guarantee each.
>>>>>> I want to start one more. What shall I do not to break guarantees?
>>>>> Don't start the new container or change the guarantees of the
>>>>> existing
>>>>> ones
>>>>> to accommodate this one :) The QoS design (done by the administrator)
>>>>> should
>>>>> take care of such use-cases. It would be perfectly ok to have a
>>>>> container
>>>>> that does not care about guarantees to set their guarantee to 0
>>>>> and set
>>>>> their limit to the desired value. As Chandra has been stating we
>>>>> need two
>>>>> parameters (guarantee, limit), either can be optional, but not both.
>>>> If I set up 9 groups to have 100Mb limit then I have 100Mb assured (on
>>>> 1Gb node)
>>>> for the 10th one exactly. And I do not have to set up any guarantee as
>>>> it won't affect
>>>> anything. So what a guarantee parameter is needed for?
>>> This use case works well for providing guarantee to one container.
>>> What if
>>> I want guarantees of 100Mb and 200Mb for two containers? How do I setup
>>> the system using limits?
>> You may set any value from 100 up to 800 Mb for the first one and
>> 200-900Mb for
>> the second. In case of no other groups first will receive its 100Mb for
>> sure and
>> so does the second. If there are other groups - their guarantees should
>> be concerned.
>
> If I add another group with a guarantee of 100MB, then its limit will
> be anywhere between 100MB-800MB ?
I've described this in details in my letter to sekharan@.
>
> I do not understand the guarantees being concerned part.
>
>>> Even I restrict everyone else to 700Mb. With this I cannot be sure that
>>> the remaining 300Mb will be distributed as 100Mb and 200Mb.
>> There's no "everyone else" here - we're talking about a "static" case.
>> When new group arrives we need to recalculate guarantees as you said.
>
> I was speaking in general where we have 'n' groups, so thats why I had
> "everyone else".
Well, when we talk about guarantee this implies that the number
of group doesn't chage - when it does limits/guarantees generally
must be recalculated to satisfy new group set.