btrfs send/receive in reverse possible?

btrfs send/receive in reverse possible?

[Sampson Fung]

I have snapshot A on Drive_A.
I send snapshot A to an empty Drive_B.  Then keep Drive_A as backup.
I use Drive_B as active.
I create new snapshot B on Drive_B.

Can I use btrfs send/receive to send incremental differences back to Drive_A?
What is the correct way of doing this?

Regards,
Sampson

Re: btrfs send/receive in reverse possible?

[Hugo Mills]

[-- Attachment #1: Type: text/plain, Size: 802 bytes --]

On Fri, Feb 16, 2018 at 10:43:54AM +0800, Sampson Fung wrote:
> I have snapshot A on Drive_A.
> I send snapshot A to an empty Drive_B.  Then keep Drive_A as backup.
> I use Drive_B as active.
> I create new snapshot B on Drive_B.
> 
> Can I use btrfs send/receive to send incremental differences back to Drive_A?
> What is the correct way of doing this?

   You can't do it with the existing tools -- it needs a change to the
send stream format. Here's a write-up of what's going on behind the
scenes, and what needs to change:

https://www.spinics.net/lists/linux-btrfs/msg44089.html

   Hugo.

-- 
Hugo Mills             | I can't foretell the future, I just work there.
hugo@... carfax.org.uk |
http://carfax.org.uk/  |
PGP: E2AB1DE4          |                                            The Doctor

[-- Attachment #2: Digital signature --]
[-- Type: application/pgp-signature, Size: 836 bytes --]