[virt-tools-list] Live migration of iscsi based targets

[Gildas Bayard]

Hello,

I thank you very much for sharing your knowledge with me.

My VMs got defined by virt-manager with
<driver name='qemu' type='raw'/>
At first I'll give a try to Justin's configuration tweak and let you 
know what happen if I change it to
<driver name='qemu' type='raw' cache='none'/>

I'm also really happy to know how to dynamically add or remove an iscsi 
LUN from my server.

Have a nice day.
Gildas

Le 28/10/2010 00:05, Justin Clift a écrit :
> On 10/28/2010 06:06 AM, Mark van Walraven wrote:
>    
>> On Wed, Oct 27, 2010 at 11:10:25AM +0200, Gildas Bayard wrote:
>>      
>>> My understanding is that blade A got it's iscsi disk cache up and
>>> running and that when the VM comes back, blade A has no way to know that
>>> the VM got its disk altered by its stay on blade B for a while. Hence
>>> the corruption.
>>>        
>> Another possible reason is caching by KVM.  Check in the<disk>  element
>> of the domain definition for one like:
>>
>>        <driver name='qemu' cache='none'/>
>>
>> Without it, KVM defaults to 'writethrough' caching, which is not safe
>> for migration.
>>      
> Gildas, are you ok to check this setting and let us know if it helps
> you?
>
> This one setting seems like it's what you might need, and could be
> a simple fix.  It *might* affect your virtual machine's performance
> though. (not sure)
>
> Phil's end-to-end configuration sounds really useful too, but a
> bit more involved to adapt if there's an easy fix. :)
>
>
>
>
>
>    

-- 
*Gildas Bayard*
Responsable de l'équipe Assistance Informatique et Technique
Laboratoire HEUDIASYC - UMR CNRS 6599
UTC Centre de Recherches de Royallieu
BP 20529 - 60205 Compiègne Cedex
Tél. 03 44 23 46 71
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