On 08/12/15 08:35 AM, Ulrich Windl wrote:
>>>> "Lentes, Bernd" <[email protected]> schrieb am 08.12.2015 
>>>> um
> 13:10 in Nachricht <[email protected]>:
>> Ulrich wrote:
>>
>>>
>>>>>> "Lentes, Bernd" <[email protected]> schrieb
>>> am
>>>>>> 08.12.2015 um
>>> 09:13 in Nachricht <00a901d13190$5c6db3c0$15491b40$@helmholtz-
>>> muenchen.de>:
>>>> Digimer wrote:
>>>>
>>>>>>>> Should I install all vm's in one partition or every vm in a
>>>>>>>> seperate partition ? The advantage of one vm per partition is
>>>>>>>> that I don't need a cluster fs, right ?
>>>>>>>
>>>>>>> I would put each VM on a dedicated LV and not have an FS
>>> between
>>>>> the
>>>>>>> VM and the host. The question then becomes; What is the PV? I
>>> use
>>>>>>> clustered LVM to make sure all nodes are in sync, LVM-wise.
>>>>>>
>>>>>> Is this the setup you are running (without fs) ?
>>>>>
>>>>> Yes, we use DRBD to replicate the storage and use the /dev/drbdX
>>>>> device as the clustered LVM PV. We have one VG for the space (could
>>>>> add a new DRBD resource later if needed...) and then create a
>>>>> dedicated LV per VM.
>>>>> We have, as I mentioned, one small LV formatted with gfs2 where we
>>>>> store the VM's XML files (so that any change made to a VM is
>>>>> immediately available to all nodes.
>>>>>
>>>>
>>>> How can i migrate my current vm's ? They are stored in raw files (one
>>>> or two).
>>>> How do I transfer them to a naked lv ?
>>>
>>> For migration the image must be available on both nodes (thus gfs2).
>>>
>>>>
>>
>> Hi Ulrich,
>>
>> the migration i meant is the transition from my current setup (virtual
>> machines in raw files in a partition with filesystem) to the one
>> anticipated in the cluster (virtual machines in blank logical volumes
>> without fs). How can I do that ? And can I expand my disks in the vm
>> afterwards if necessary ?
> 
> You can copy the images with rsync or similar while the VMs are down. Then 
> you'll have the same filesystem layout. If you want to change the partition 
> sizes, I'd suggest to create new disks and partitions, the mount the 
> partitions on old and new system, and then rsync (or similar) the _files_ 
> from OLD to NEW. Some boot loaders may need some extra magic. If you use LVM, 
> you might just add another disk to the VM, then make that disk a PV and add 
> it to the VG. Then you can expand your LVs inside the VM.
> 
>> But the "other" migration (live-migration of vm's) is of course also
>> interesting. Digimer wrote if I have my vm in a blank logical volume
>> without fs, which is placed on a SAN, I can live-migrate because the
>> process of live-migration takes care about the access to the lv and I
>> don't need a cluster fs, just cLVM.
> 
> If logical volume means LUN (disk), I'd agree. If you mean LVM LV, I'd be 
> very careful, especially when changing the LVM configuration. If you never 
> plan to change LVM configuration, you could consider partitioning your disk 
> with GPT with one partition for each VM.
> 
> Regards,
> Ulrich

This approach is to do it from the VM's level, and it is not needed. The
VM does need to be stopped, yes, but you can simple go from a raw format
to the LV using dd, in my experience.

-- 
Digimer
Papers and Projects: https://alteeve.ca/w/
What if the cure for cancer is trapped in the mind of a person without
access to education?

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