[pve-devel] Incremental backups

[Kamil Trzciński]

Hi Eneko,

My patches try to add one of missing features, but the way it works is
not very efficient, because it uses xdelta3 to create differential. It
not only uses extra CPU cycle, but also requires you to read
previously done backup. In the future it should be done on qemu level.
Qemu should track what did exactly change and make incremental backup
from only changed bits. Similar approach is described here:
http://wiki.qemu.org/Features/Livebackup

I think that this is completely fine that it's not merged. Just
because it is an extension which you can install you should also
understand what drawbacks it has. If it got merged there might be some
confusion about this feature, because it doesn't work well for large
number VMs or extremely large ones.

Kamil

On Fri, Sep 19, 2014 at 11:41 AM, Eneko Lacunza <elacunza at binovo.es> wrote:
> Hi Martin,
>
> On 19/09/14 11:07, Martin Maurer wrote:
>>>
>>> I just found out about this blog:
>>> http://ayufan.eu/projects/proxmox-ve-differential-backups/
>>>
>>> You surely know about it; I was curious about the reasons to reject the
>>> patches
>>> and also about whether there are any plans for incremental or
>>> differential
>>> backups. I think it would be a popular feature with our paying clients.
>>
>> The reason why this is not included is already discussed on this list.
>> => read the archives.
>>
> If you're pointing to this thread:
> http://pve.proxmox.com/pipermail/pve-devel/2012-August/thread.html#3412
>
> I hardly see any discussion, just a no-statement with a vague "we want to
> keep vzdump simple" and no reply to Kamil's last message where he points-out
> that his changes are small. He has even kept the patches up-to-date with
> Proxmox versions.
>
> The feature is very interesting for remote-copying backups and keeping
> backup storage size lower. I can understand that maybe technical reasons
> favor another solution against this, but this doesn't seem the case?
>
> Eneko
>
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-- 
Kamil Trzciński

ayufan at ayufan.eu
www.ayufan.eu