SLA feature for storage I/O bandwidth

[Doron Fediuck]

----- Original Message -----
> From: "Mei Liu" <liumbj at linux.vnet.ibm.com>
> To: "Dave Neary" <dneary at redhat.com>
> Cc: arch at ovirt.org
> Sent: Wednesday, May 29, 2013 11:35:12 AM
> Subject: Re: SLA feature for storage I/O bandwidth
> 
> On 05/29/2013 03:42 PM, Dave Neary wrote:
> > Hi Mei Liu,
> >
> > On 05/28/2013 10:18 AM, Mei Liu wrote:
> >> I created a drafted wiki page on  design of storage I/O bandwidth SLA in
> >> the following link:
> >>
> >> http://www.ovirt.org/SLA_for_storage_resource .
> >>
> >> I will appreciate the efforts if anyone who works on ovirt engine, vdsm
> >> or mom could give some comments. TIA.
> > Just out of interest - which version of oVirt are you targeting this
> > for? Can I assume that it's for post-3.3? Today is officially 3.3.
> > feature freeze (but we have a release meeting later to discuss that).
> >
> > Thanks,
> > Dave.
> >
> Hi Dave,
> The basic i/o tune functionality for vdsm is almost ready. However,
> there is nothing written on the Engine side and no policy for automatic
> tuning is applied yet.
> I am not sure if the basic functionality can target 3.3.
> 
> 
> Best regards,
> Mei Liu
> 

Hi Mey Liu,
I'm still going over the wiki, but a few things we need to consider;
First of all QoS for storage I/O bandwidth is a part of a larger SLA
policy which may include network QoS, CPU and memory QoS and the quota
we implement today.

So first of all we need to make sure your design does not conflict
the other QoS parts, which is what I'm looking into now. 

Additionally, using the quota term is confusing as oVirt already has
quota today, and cpu API has his own quota definition. So please try
to come up with a different terminology.

I like your idea of setting an initial value but I need some more time
for it to come up with my insights.
Also, I completely agree with your concept of letting mom handle
it in host level. We need to verify it does not break anything related
to SPM. This is something we need to synchronize with the storage guys.

Looking into the engine area, we should start thinking on how this will
be supported in the main storage entities and VM / template / instance
entities. So you may want to add a section on this as well. This leads
me to think of importing and exporting a VM which may want to maintain
the defined IO QoS. Any thoughts around it?

Doron