[PVE-User] LVM Snapshot on Proxmox 2.2

[Daniel Vuilleumier]

Hello

Thank you for this clarification, Mark and Alain!

So, I assume, under Proxmox 1.9 the 4GB Free PE was not enough to enable snapshots without downtime (at least in my case).

If I get you right, there is no need to free additional space in Proxmox 2.2? 
Is there an easy way to calculate how much space will be needed, f.e. for a 300GB heavily used container?

Regards,
Daniel



Am 14.02.2013 um 15:33 schrieb Alain Péan <alain.pean at lpn.cnrs.fr>:

> Hello,
> 
> Yes, it's right, you need only the space to store the changes. By default, I think  Proxmox ve 1.x installation leaved 4 GB of empty space in volume group, but it may be insufficient if backup takes time, or if the VM is heavily used. It seems that in PVE 2.2, Proxmox installation leaves 16 GB :
> root at proxmoxtest00:~# vgdisplay
>   --- Volume group ---
>   VG Name               pve
>   System ID
>   Format                lvm2
> ....
>   VG Size               297.59 GiB
>   PE Size               4.00 MiB
>   Total PE              76183
>   Alloc PE / Size       72088 / 281.59 GiB
>   Free  PE / Size       4095 / 16.00 GiB
> 
> Alain
> 
> Le 14/02/2013 15:17, Mark Ehle a écrit :
>> I might be wrong, but I am under the impression that the spare space only has to equal the changes that take place between the snapshot and the filesystem while the snapshot exists.       
>> 
>> 
>> On Thu, Feb 14, 2013 at 4:52 AM, Daniel Vuilleumier <vui at bitnpixel.com> wrote:
>> Hello
>> 
>> Does anybody know whether the "live snapshot" requires us to have empty space on the logical volume group in both cases: local backup and backup to NFS?
>> 
>> For example:
>> My LVM is 1.8TB (maximum size on HW-RAID10).
>> I want to live snapshot a 100GB Container.
>> 
>> Do I have to shrink the logical volume to 1.7TB in order to get the snapshot done without downtime?
>> 
>> In Proxmox 1.9 this used to be the case, does it still apply to 2.2 (and forthcomeing 2.3)?
>> 
>> Regards
>> Daniel Vuilleumier
>> Zurich, Switzerland
>> 
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