Re: [Engine-devel] VM hibernation to storage domain
On 12/12/2011 21:04, Jon Choate wrote:
On 12/12/2011 01:46 PM, Yaniv Kaul wrote:
> On 12/12/2011 19:22, Jon Choate wrote:
>> Is there any reason anyone can think of why we would need to specify
>> a specific storage domain for a VM to use when it hibernates?
>> Ideally we could just grab any storage domain that has space and use
>> it for hibernation (as long a we remember where we did it!).
>>
>> thoughts?
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>
> Probably for the same reason we enforce all VMs disks to be on the
> same storage domain. Habit.
Eliminating this dependency would be part of the feature to allow VMs
to have their disks on multiple storage domains.
> But I also think it make sense, for the hibernation file to be in the
> same SD as the system disk. There's also a higher chance that domain
> will be online and available to the host.
> Y.
Is it possible for ovirt-engine to identify which disk is the system
disk?
In several ways:
1. Guess.
2. The first
3. Use the one with the 'Is Bootable' flag.
Y.
What should the algorithm be for determining a storage domain to
hibernate a diskless VM?
None, we should only support S4 and say farewell to the external
hibernation. I don't think there is a good enough reason to keep it
(Ayal might disagree, but I disagree with his reasons).
It seems like things would be simplified if we did not restrict
ourselves and could use any available storage domain regardless of
whether the vm has disks or not.
Perhaps. What's the real benefit, except of freedom of choice? I
personally would look at compressing that hibernation file, btw. Always
annoyed me the size of it, and I expect fast compression to enable
faster suspend-resume cycles. I believe libvirt support some compression
methods.
Y.