add blkIoTune support for a specific device at vm creation

[Eli Mesika]

----- Original Message -----
> From: "Mei Liu" <liumbj at linux.vnet.ibm.com>
> To: "Eli Mesika" <emesika at redhat.com>, "Dan Kenigsberg" <danken at redhat.com>
> Cc: "Doron Fediuck" <dfediuck at redhat.com>, arch at ovirt.org
> Sent: Tuesday, May 28, 2013 11:03:49 AM
> Subject: Re: add blkIoTune support for a specific device at vm creation
> 
> On 05/26/2013 09:28 PM, Eli Mesika wrote:
> >
> > ----- Original Message -----
> >> From: "Dan Kenigsberg" <danken at redhat.com>
> >> To: "Doron Fediuck" <dfediuck at redhat.com>, "Eli Mesika"
> >> <emesika at redhat.com>
> >> Cc: "Mei Liu" <liumbj at linux.vnet.ibm.com>, arch at ovirt.org
> >> Sent: Thursday, May 23, 2013 6:36:42 PM
> >> Subject: Re: add blkIoTune support for a specific device at vm creation
> >>
> >> On Wed, May 22, 2013 at 11:55:26AM -0400, Doron Fediuck wrote:
> >>> ----- Original Message -----
> >>>> From: "Mei Liu" <liumbj at linux.vnet.ibm.com>
> >>>> To: arch at ovirt.org
> >>>> Cc: dfediuck at redhat.com, wudxw at linux.vnet.ibm.com
> >>>> Sent: Monday, May 20, 2013 6:07:53 AM
> >>>> Subject: add blkIoTune support for a specific device at vm creation
> >>>>
> >>>> Hi all,
> >>>> I would like to add blkIoTune support for a specific device at vm
> >>>> creation.
> >>>>
> >>>> The code parses the 'blkIoTune' descrption for block devices at vm
> >>>> creation
> >>>> time and adds iotune tag accordingly.
> >>>>
> >>>> e.g.
> >>>> Adding 'blkIoTune':{'read_bytes_sec': 6120000, 'total_iops_sec': 800}
> >>>> for
> >>>> a
> >>>> block device will add the following in dom xml for that device.
> >>>>
> >>>> <iotune>
> >>>>        <read_bytes_sec>6120000</read_bytes_sec>
> >>>>        <total_iops_sec>800</total_iops_sec>
> >>>> </iotune>
> >>>>
> >>>> The patch is under review in http://gerrit.ovirt.org/#/c/14636/ .
> >>>>
> >>>> Does the patch meet the requirement of the engine or the whole
> >>>> architecture? Are the new parameters properly placed?  Any suggestions
> >>>> are welcomed.
> >>>>
> >>>> TIA.
> >>>>
> >>>> Best reagrds,
> >>>> Mei Liu (Rose)
> >>>>
> >>>>
> >>> Hi Mei Liu,
> >>> Apologies for my late response.
> >>> Is there an engine implementation for it?
> >>> This is important enough to be considered on how it works in a cluster
> >>> on not just on host level. For example, what happens during and after
> >>> live migration?
> >> As far as I know, there's nothing written on the Engine side, yet.
> >>
> >> And in my opinion, we can aim low, and have a very minimalistic
> >> implementation, that give a thin GUI for each block device, in where
> >> these two parameters can be edited, and passed to Vdsm on vmCreate,
> >> hotplug, and vmUpdateDevice.
> >>
> >> Obviously, such an implementation affects only in the vDisk level; the
> >> io throttling would follow the VM to the destination node, regardless of
> >> other readers/writers on that host. This is suboptimal; it would be
> >> cooler to have a policy that provides relative io priority to different
> >> vDisks/VMs/users. But in my opinion, it can wait for a second phase.
> >>
> >> I'm fine with the suggested Engine/Vdsm API (though I'd try to be even
> >> more just-like-libvirt and call it "iotune"). But I'm no Engine expert
> >> to judge - the may wnat to hide it in their specParam map.
> > Right, ant reason why not to use the specParam
> > s here ???
> 
> No specific reason for doing so. I moved them to specParams.

Thanks

> 
> 
> >
> >> I'd love to see a feature page written for this, anyway!
> >>
> >>
> >> Dan.
> >>
> I have updated the patch in http://gerrit.ovirt.org/#/c/14636/ and put
> these parameters in specParams.
> Appreciate that you take a look and give suggestions.

Looks good , gave +1

> 
>