On Wed, Jul 30, 2008 at 12:16 AM, Mark Williamson
<mark.williamson@cl.cam.ac.uk> wrote:> On Tuesday 29 July 2008, you wrote:
>> Hi Mark
>>
>> I have some queries on Xen Migration setup
>>
>> VM resource are provided using NFS, iSCSI, AoE. After following the
>> below article
http://archive.netbsd.se/?ml=xen-users&a=2007-12&t=6000155.
>> It suggests that we can migrate the disk and swap images using
>> external-device-migration.
>
> Heh, well it looks like I suggested that but I''ve never done it
myself! I
> believe it may be possible but it won''t necessarily be efficient.
>
>> So it means that if we use the external-device-migrate script then all
>> the shared reosurce methos are not required ?
>
> In *principle*, if I was right about the external device migration scripts
> then it might eliminate the need for shared resources. But unless you
added
> some clever tricks then it would make live migration slower because of the
> need to copy the data across. I think a good network-based disk solution
> will perform better since the disk and swap will be available immediately
> after the memory migration has been performed.
>
>
>> How do i use this method (to migrate the machine with device
>> migration)?
>
> Sorry, I don''t know the details. I guess you''d have to
write a script that
> would do the device migration somehow (e.g. copying files across a network)
> and get the migration system to call it. Sorry I can''t be more
specific.
>
>> Does xm migrate take care of using the device migration
>> scripts if shared resource (NFS, AoE etc) are not used.
>
> Not automatically, you''d need to tell it to use the migration
scripts. There
> might be some example scripts in the Xen repository you could look at but
> you''d probably have to do some customisation or possibly write
your own.
>
>> or Am i missing something important.
>
> It''s easy to set up Xend to automatically connect to nbd devices
when a
> migration occurs. Maybe you should consider that?
>
> In any case, you should take care to separate the migration traffic from
the
> VM''s network somehow so that VMs can''t snoop on the data
transmitted by
> migrations.
thanks for all your helpful pointers.
>
> Cheers,
> Mark
-Tej>
> --
> Push Me Pull You - Distributed SCM tool
(http://www.cl.cam.ac.uk/~maw48/pmpu/)
>
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