[pve-devel] VM snapshot problem

Alexandre DERUMIER aderumier at odiso.com
Fri Aug 24 11:16:44 CEST 2012


>>The problem with that is that most users use LVM, NFS or RAW files on local storage.
>>So how can we snapshot such images?
>> 
>>For NFS and RAW files we can create and external snapshot (base image + writable image file)?
I don't think it's possible. this is main reason why qcow2 exist.
for nfs,it's possible if you have a san/nas which support snapshot on his filesytem. Like netapp nfs for exemple. (but need to implement snapshot api)
For local raw file, it should be possible with zfs or btrfs.  (remote linux nfs storage with zfs,btrfs should work too, implement snasphots via ssh commands)

(but you can convert raw to qcow2 also)

I known that qemu developper are currently working for optimize qcow2 performance.


>> But how can we handle LVM (lvm snapshots on shared storage does not work at all)? 
I really don't know.
for "new" lvm format (dm-thinp) , it doesn't work.
For "old" lvm format, maybe. (But I have read some articles with bad performance about it)

Don't you use already lvm snapshot for backups ?


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

De: "Dietmar Maurer" <dietmar at proxmox.com> 
À: "Alexandre DERUMIER (aderumier at odiso.com)" <aderumier at odiso.com>, pve-devel at pve.proxmox.com 
Envoyé: Vendredi 24 Août 2012 10:31:02 
Objet: VM snapshot problem 



>From what I see the following storage drivers provides internal snapshots: 

QCOW2 files 
sheepdog 
rbd 
nexenta (not fully functional) 

The problem with that is that most users use LVM, NFS or RAW files on local storage. 
So how can we snapshot such images? 

For NFS and RAW files we can create and external snapshot (base image + writable image file)? 

But how can we handle LVM (lvm snapshots on shared storage does not work at all)? 

- Dietmar 



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