boot from snapshot and take snapshot from here.

boot from snapshot and take snapshot from here.

[Jakob Schürz]

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Hi there!

I can't find any Information for my Problem. And I try to explain, what
I want.

There is a btrfs-partition on my laptop.
I take snapshots every hour from the subvolume @debian.

btrfs subvol snapshot @debian @debian-snap1

Then I transfer this snapshot to my external HD

btrfs send @debian-snap1 | btrfs receive /backupmountpoint

The next snapshot

btrfs subvol snapshot @debian @debian-snap2

Transfer is

btrfs send -p @debian-snap1 @debian-snap2|btrfs receive /backupmountpoint

No magic here, works fine.

BUT

When i boot from f.e. @debian-snap2, the mechanics doesn't work any longer.

btrfs subvol snapshot @debian-snap2 @debian-snap3

this works.

btrfs send -p @debian-snap2 debian-snap3 | btrfs receive /backupmountpoint

gives me an error, that btrfs can't find a subvol with a proper ID.

Ho to do this, if i want to boot from a former snapshot (in case of a
mistaken system-upgrade) and i want to transfer the later snapshots to
the external HD - only the differences?

There is nothing on the internet on this problem (I've found). But i
think this is a usecase, which I'm not alone needing it...

jakob

-- 
http://xundeenergie.at
http://verkehrsloesungen.wordpress.com/
http://cogitationum.wordpress.com/


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Re: boot from snapshot and take snapshot from here.

[Hugo Mills]

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On Sat, Nov 07, 2015 at 08:04:01PM +0100, Jakob Schürz wrote:
> Hi there!
> 
> I can't find any Information for my Problem. And I try to explain, what
> I want.
[snip]
> BUT
> 
> When i boot from f.e. @debian-snap2, the mechanics doesn't work any longer.
> 
> btrfs subvol snapshot @debian-snap2 @debian-snap3
> 
> this works.
> 
> btrfs send -p @debian-snap2 debian-snap3 | btrfs receive /backupmountpoint
> 
> gives me an error, that btrfs can't find a subvol with a proper ID.
> 
> Ho to do this, if i want to boot from a former snapshot (in case of a
> mistaken system-upgrade) and i want to transfer the later snapshots to
> the external HD - only the differences?

   Basically, you can't right now. It's a known limitation, and can, I
think, be fixed, but it'll need a change to the send stream format,
which is a tricky migration to do (because there's currently no format
identifier in it, which makes it hard to handle both formats easily).

> There is nothing on the internet on this problem (I've found). But i
> think this is a usecase, which I'm not alone needing it...

   You're not alone. It will come eventually, but only when David's in
a position to deal with the issues of changing the send stream.

   Hugo.

-- 
Hugo Mills             | "No! My collection of rare, incurable diseases!
hugo@... carfax.org.uk | Violated!"
http://carfax.org.uk/  |
PGP: E2AB1DE4          |                Stimpson J. Cat, The Ren & Stimpy Show

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Re: boot from snapshot and take snapshot from here.

[Jakob Schürz]

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Am 2015-11-07 um 20:18 schrieb Hugo Mills:
> On Sat, Nov 07, 2015 at 08:04:01PM +0100, Jakob Schürz wrote:
>> Hi there!
>>
>> I can't find any Information for my Problem. And I try to explain, what
>> I want.
> [snip]
>> BUT
>>
>> When i boot from f.e. @debian-snap2, the mechanics doesn't work any longer.
>>
>> btrfs subvol snapshot @debian-snap2 @debian-snap3
>>
>> this works.
>>
>> btrfs send -p @debian-snap2 debian-snap3 | btrfs receive /backupmountpoint
>>
>> gives me an error, that btrfs can't find a subvol with a proper ID.
>>
>> Ho to do this, if i want to boot from a former snapshot (in case of a
>> mistaken system-upgrade) and i want to transfer the later snapshots to
>> the external HD - only the differences?
> 
>    Basically, you can't right now. It's a known limitation, and can, I
> think, be fixed, but it'll need a change to the send stream format,
> which is a tricky migration to do (because there's currently no format
> identifier in it, which makes it hard to handle both formats easily).
> 
>> There is nothing on the internet on this problem (I've found). But i
>> think this is a usecase, which I'm not alone needing it...
> 
>    You're not alone. It will come eventually, but only when David's in
> a position to deal with the issues of changing the send stream.

OK!

I'm always happy, when i realize, it's not my tired mind, when i can't
find the solution :)

Thanks for the  info. So we will wait.

jakob


-- 
http://xundeenergie.at
http://verkehrsloesungen.wordpress.com/
http://cogitationum.wordpress.com/


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