Ken D'Ambrosio <> writes:

> On 2022-02-24 11:31, Ian Kelling wrote:
>> Chuck McAndrew <> writes:
>>> I would add one feature about ZFS that is super useful and that is
>>> the ability to replicate datasets to a remote server. I don't know if
>>> btrfs has a
>>> similar feature, but the ability to have a backup server offsite and
>>> just setup a cron job to replicate it was awesome for DR. It makes
>>> backing up
>>> your snapshots very very easy.
>> Yes, btrfs has this. I use it mostly through this tool:
>> . I recommend it.
> I use the btrfs-send (which, of course, is modeled after
> zfs-send)... except, I kinda don't.  And this isn't a dig at btrfs (or
> ZFS), but just paranoia: I'm afraid that, if there were corruption on
> the source FS, using a FS-specific/replicating tool to do the data
> transfer might bring over whatever corruption was on the source in the
> first place.
> So what I do:
> * Create a copy on the destination host.
> * Snapshot it.
> * Mount the snapshot as my rsync backup destination.
> * And make a snapshot of _that_.
> That way, I have two essentially identical CoW hierarchies, but that
> have "left" the source FS, and gone to the destination one.  Not as
> efficient as sending CoW deltas, but it gives me a little more peace of
> mind.  Yes, my scenario seems awfully unlikely, buuuuuuuuuut...

I'm confused by those bullets, I understand the general idea though.

I think that it is a valid concern. I don't worry about btrfs send
deleting data, so much as a filesystem having some metadata error
propagated that you need a btrfs expert to help you correct before you
can mount it read-write. The same concern applies to ZFS. It reminds me
of the 2 media types recommendation of 3-2-1 backup strategy

An rsync-like solution is simpler and more flexible in a bunch of ways,
and even more performant in some ways. For FSF servers, we use a restic
wrapper we wrote,  btrfs-send and
wrappers like btrbk are not my first recommendation for backups unless
someone really wants or needs their specific benefits.

Ian Kelling | Senior Systems Administrator, Free Software Foundation
GPG Key: B125 F60B 7B28 7FF6 A2B7  DF8F 170A F0E2 9542 95DF |
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