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From Bharat Kumar <>
Subject Re: [Discuss] Cpu and Ram overcommit.
Date Thu, 17 Jan 2013 17:30:36 GMT
Alex thank you for your suggestions, I  will add them to the functional spec.


On Jan 16, 2013, at 4:19 AM, Alex Huang <> wrote:

> Bharat,
> A few comments.
> - On your caveats, I think you should deploy 2b.  Accept the change but not add more
VMs anymore.  You can provide a warning.
> - As for repeated alerts, that's a problem with the alert mechanism.  It should not repeat
alerts.  Fix it there.
> On implementation:
> - You need to add something more generic such as a cluster-details to cluster that allows
you retrieve what you want to add to it.  I don't see any reason to keep adding columns to
cluster/pods.  Cluster/pods are organization units.  We should add a details table (might
already there) to keep component details because no one else will use this detail information.
 I don't see why we need to add database columns for this.
> - How are you planning to handle hypervisors that cannot overcommit cpu or ram?  To me
this needs capabilities added to the hypervisor caps table.
> - This is a planner specific change.  Make sure the changes are localized in the planner.
 If there's anything you need to change in CloudStack core/server, please point that out in
a subtask for your bug and let me know.
> --Alex
>> -----Original Message-----
>> From: Bharat Kumar []
>> Sent: Tuesday, January 08, 2013 3:16 AM
>> To:
>> Cc:
>> Subject: Re: [Discuss] Cpu and Ram overcommit.
>> Hi Hari,
>> A host can have more than one tag so we need not overwrite the inherited
>> cluster  tag of a host, if a host specific tag is added.
>> Bharat
>> On Dec 26, 2012, at 11:32 AM, Bharat Kumar <>
>> wrote:
>>> Hi all,
>>> Presently in Cloudstack  there is a provision for cpu overcommit and no
>> provision for the ram overcommit. There is no way to configure the
>> overcommit ratios on a per cluster basis.
>>> So we propose to add a new feature to allow the ram overcommit and to
>> specify the overcommit ratios ( cpu/ram ) on a per cluster basis.
>>> Motivation to add the feature:
>>> Most of the operating systems and applications do not use the allocated
>> resources to 100%. This makes it possible to allocate more resource than
>> what is actually available.  The overcommitting of resources allows to run the
>> underutilized VMs in fewer number of hosts, This saves money and power.
>> Currently the cpu overcommit  ratio is a global parameter which means there
>> is no way to fine tune or have a granular control over the overcommit ratios.
>>> This feature will enable
>>> 1.) Configuring the overcommit ratios on a per cluster basis.
>>> 2.) ram overcommit feature in xen and kvm. ( It is there for VMware.)
>>> 3.) Updating the overcommit ratios of a cluster.
>>> Regards,
>>> Bharat Kumar.

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