[Engine-devel] Low Level design for HotPlug/HotUnplug feature

Dor Laor dlaor at redhat.com
Mon Jan 9 10:17:39 UTC 2012


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
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>
> 1. Corrected some typos, spelling, backend->engine, 'REST API' -> 'API',
> etc. (didn't fix ' storage procedures' - but I think you've meant
> 'stored procedures' ?).
> 2. Missing/questions:
> - Permissions? Quota?
> - Explain how disk is created in the first place.
> - Database (tables, etc.)
> - Which cluster level is required?
> - Is it an async or sync task?
> - Can you plug a system disk?
> - Can you unplug multiple at a time?
> - What happens when you plug too many?
> - How do you determine where (PCI bus-wise) to plug them?
> - Any CanDoAction to allow/disallow plug/unplug from specific systems?
> - I suspect we'd be happier with some agent cooperation before
> unplugging - is this done by QEMU? Not detailed anywhere.
> - Link to KVM/QEMU feature description for it, if such exist, would be nice.
> - Does it affect taking a snapshot? Live or not?
> - Does it affect exporting a VM? I reckon you export with all disks,
> with their plug/unplug status?

In addition:
  - will you allow it during live migration (qemu allows it)?
  - Are you expecting events to pop?
  - You call it 'hotplug' but mention only disk device, what about
    memory/cpu/ any other pci card?
  - How do you define a system disk? Some VM may boot from
    pxe/nfsroot/etc
  - 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

>
> Y.
>
>
>
>
>
>
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> http://lists.ovirt.org/mailman/listinfo/engine-devel




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