# Re: Encrypted software RAID1 with Debian Stretch

- From: Nix \<hidden\>
- Date: 2017-09-15 11:35:41 
- List: linux-raid
- Page: https://ratatoskr.run/linux-raid/2017/09/6636784
- Thread: https://ratatoskr.run/linux-raid/2017/09/6636784/t.md

```text
On 14 Sep 2017, Roman Mamedov said:

> On Thu, 14 Sep 2017 16:02:31 +0100
> Nix [ref] wrote:
>
>> I would never consider snapshots on the same filesystem to be a backup
>> of anything, except possibly as a defence against 'oh whoops I rm'ed the
>> wrong tree'.
>
> No one proposed that.

Oh I thought that was what people were proposing as the compelling btrfs
advantage.

>                       The scenario is that the backup server would have its
> rsync destination dir (from multiple other systems) periodically snapshotted,
> providing a historic view of what it contained 1-2-3 months ago. Just like
> "bup" does in userspace, I guess? -- or like rdiff-backup did, which I used
> before. But now we have that directly in filesystem, no need to cling to
> userspace crutches anymore.

I'm fairly sure that can't deduplicate anywhere near as effectively. No
dedup within files; no dedup across trees (very important if you have
duplicated data on multipl systems you are backing up); no dedup
anywhere except in immediate history. That's all rdiff-backup could do,
but the state of the art is better now.

-- 
NULL && (void)
```