Proxmox differential backup and Windows servers

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Darkhunter

New Member
Aug 21, 2015
19
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1
Hello,
I know, that u don't support differential backups, but I don't know better forum, where can I get an advice.
We have many proxmox servers and many VMs in them, so we are not able to handle more than three full backups for VMs.
I found a way to spare some place by using differential backups. It is using xdelta3 to make diffs.
I have two problems:
1) Xdelta3 uses only single core, so it is very slow. Is there any way to make it use more cores?
2) Windows servers diff backups have almost same size as full backups or sometimes they are even bigger!!! It's because xdelta3 doesn't work well with ntfs. I found a way to make it better by moving pagefile on different disk, which wouldn't be backuped. That way didn't work. Is there a better way?

Thanks for help!
 
Hi,

thanks for your reply, but I don't think we can use it, because we use Virtio on Windows servers (it should be faster than IDE).
 
You can use virtio with zfs.
why not?.
 
Okay,I'm running virtuals on ZFS right now. Is there any way to send snapshot directly to storage server? I don't have space on proxmox for snapshotting all the VMs, so is there any way to make snapshot directly on storage server?
 
The best thing would be that the backup server is also ZFS. That way you can use ZFS send/receive over SSH ( http://docs.oracle.com/cd/E19253-01/819-5461/gbinw/ ). The next thing is to receive the destination backups in a file but that sucks. You do something like this:
- zfs snapshot VM1@1
- zfs send VM1@1 | ssh backup dd of=VM1.zfs

then you do some incrementals, all based on 1

- zfs snapshot VM1@1.1
- zfs send -i VM1@1 VM1@1.1 | ssh backup dd of=VM1.1.zfs
- zfs snapshot VM1@1.2
- zfs send -i VM1@1.1 VM1@1.2 | ssh backup dd of=VM1.2.zfs

So you will have initial backup VM1.zfs and lots of incrementals VM1.1.zfs VM1.2.zfs and so on. You will need to apply them in order (using zfs recv) when doing recovery.

After a week or whatever interval is good for you you need to do another full backup VM1@2 then remove all @1 backups and do incrementals for 2.1 2.2 and so on. This is required because the diffs can be larger than a full backup in time.

This is ugly and tedious so a ZFS backup server is a perfect appliance. You will do incrementals only, delete them, keep the weekly ones and so on.
 
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