8:04 a.m.
----- Original Message -----
From: "Livnat Peer" <lpeer(a)redhat.com>
To: "Michael Kublin" <mkublin(a)redhat.com>
Cc: dlaor(a)redhat.com, "Yaniv Kaul" <ykaul(a)redhat.com>,
engine-devel(a)ovirt.org
Sent: Monday, January 9, 2012 3:07:06 PM
Subject: Re: [Engine-devel] Low Level design for HotPlug/HotUnplug feature
On 09/01/12 12:17, Dor Laor wrote:
> On 01/09/2012 11:45 AM, Yaniv Kaul wrote:
>> On 01/09/2012 11:21 AM, Michael Kublin wrote:
>>> Hi, the follow link is providing a low level design for
>>> HotPlug/HotUnplug feature
>>> :http://www.ovirt.org/wiki/Features/DetailedHotPlug .
>>>
>>> The feature is simple and design is short
>>>
>>> Regards Michael
>>> _______________________________________________
>>> Engine-devel mailing list
>>> Engine-devel(a)ovirt.org
>>> http://lists.ovirt.org/mailman/listinfo/engine-devel
>>
>> 1. Corrected some typos, spelling, backend->engine, 'REST API' ->
>> 'API',
>> etc. (didn't fix ' storage procedures' - but I think you've
meant
>> 'stored procedures' ?).
Thanks
>> 2. Missing/questions:
>> - Permissions? Quota?
Regards Quota - has not influence on the feature
>> - Explain how disk is created in the first place.
The
disk is added to VM by AddDiskToVMCommand, by default is is plugged
>> - Database (tables, etc.)
They are in design
>> - Which cluster level is required?
Added to design ,
it is 3.1
>> - Is it an async or sync task?
Sync
>> - Can you plug a system disk?
No
>> - Can you unplug multiple at a time?
Yes, we have not
such limitation, the sane is to plug.
>> - What happens when you plug too many?
We allow to
plug disk which were attached to vm , by AddDiskToVmCommand, a max number of allowed disks
is handled there
>> - How do you determine where (PCI bus-wise) to plug them?
As I think, the PCI address will be added to most devices at Stable PCI device
addresses feature, I will use it
>> - Any CanDoAction to allow/disallow plug/unplug from
specific
>> systems?
The operation will be allowed only for RHEL 5/6, Windows Server
2003 and Windows server 2008 operating systems, added to design
>> - I suspect we'd be happier with some agent cooperation
before
>> unplugging - is this done by QEMU? Not detailed anywhere.
I will check
this
>> - Link to KVM/QEMU feature description for it, if such
exist,
>> would be
>> nice.
>> - Does it affect taking a snapshot? Live or not?
No, all disk will be
passed to snapshots as is
>> - Does it affect exporting a VM? I reckon you export with
all
>> disks,
>> with their plug/unplug status?
This one I need to check
> In addition:
> - will you allow it during live migration (qemu allows it)?
I don't see
any technical limitation from my side, but I will check
> - Are you expecting events to pop?
> - You call it 'hotplug' but mention only disk device, what about
> memory/cpu/ any other pci card?
The pci card it is another feature, in
current version we have only hotplug / unplug for disks and pci card
> - How do you define a system disk? Some VM may boot from
> pxe/nfsroot/etc
I had a property on the disk which means System, also I
have a property that means bootable. I suppose that
disk can not be plugged/unplugged with any of them
> - It should be a nice to have to check if the guest mounts any
FS
> within the disk to be un hot pluged and warn the user
Need to be check
In addition - 2 :
- plugged/unplugged disk is a VM property not disk's. (this of a
shared
disk that can be plugged in one VM but unplugged in another)
Ok. I will update
design
- supporting the best effort flag is not related only to hot plug
disk,
is it supported in the VDSM level on a per disk basis? again should
not
be a disk property but a VM-Disk relation property.
>>
>> Y.
>>
>>
>>
>>
>>
>>
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>
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