[pve-devel] savevm tests

Alexandre DERUMIER aderumier at odiso.com
Wed Aug 29 18:19:13 CEST 2012


>>I see no real reason why that should not be possible. But sure, you need 
>>to pre-allocate space for snapshots, which is bad. 
I'll tell the question to the qemu mailing!

> Also, zfs snapshot are really fast. 

>>But limited (no support for arbitrary snapshot trees)? 
Yes indeed. (But try to do 1000 snapshots with qcow2 ;-)

>>IMHO cloning has totally different requirements - we should not mix that. 
Yes/no : we need to snapshot for cloning (at least for sheepdog,rbd,nexenta).
         qcow2 is a little different, as cloning is just an external snapshot.
         But indeed, for now, working on snapshot is already a big work.

>>Besides, I just don't know how to implement nexenta snapshot support inside kvm. 
>>Do you want to call an external program which uses libpve-storage-perl? 
It's just an soap api. (like for create/delete nexenta volume).
But yes,it's only disk snapshot, it's not possible to save the vmstate memory.

----- Mail original ----- 

De: "Dietmar Maurer" <dietmar at proxmox.com> 
À: "Alexandre DERUMIER" <aderumier at odiso.com> 
Cc: pve-devel at pve.proxmox.com 
Envoyé: Mercredi 29 Août 2012 18:06:50 
Objet: RE: [pve-devel] savevm tests 

> >>Putting qcow2 (or better qcow3) on those devices would solve the 
> >>problem? If that works, there is no more need to use nexenta snapshot 
> support? 
> 
> I want to use iscsi with nexenta, so qcow2 is not an option. (and I'm not sure 
> using qcow2 on block device is possible) 

I see no real reason why that should not be possible. But sure, you need 
to pre-allocate space for snapshots, which is bad. 

> Also, zfs snapshot are really fast. 

But limited (no support for arbitrary snapshot trees)? 

> (qcow2 have some performance penality). 

qcow3 will be much better (maybe) ;-) 

> I also need zfs snapshot for cloning. 

IMHO cloning has totally different requirements - we should not mix that. 

> More generally, I think it's always better to use snapshot capability of the 
> storage (rbd,sheepdog,nexenta, or other). 

sure (if it is fully functional like 'rbd' and 'sheepdog' (beside bugs)) 

Besides, I just don't know how to implement nexenta snapshot support inside kvm. 
Do you want to call an external program which uses libpve-storage-perl? 



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Alexandre D e rumier 

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