Re: ERROR: parent determination failed (btrfs send-receive)

[Andrei Borzenkov <arvidjaar@gmail.com>]

18.09.2017 05:31, Dave пишет:
> Sometimes when using btrfs send-receive, I get errors like this:
> 
> ERROR: parent determination failed for <subvolume name>
> 
> When this happens, btrfs send-receive backups fail. And all subsequent
> backups fail too.
> 
> The issue seems to stem from the fact that an automated cleanup
> process removes certain earlier subvolumes. (I'm using Snapper.)
> 
> I'd like to understand exactly what is happening so that my backups do
> not unexpectedly fail.
> 

You try to send incremental changes but you deleted subvolume to compute
changes against. It is hard to tell more without seeing subvolume list
with uuid/parent uuid.

> In my scenario, no parent subvolumes have been deleted from the
> target. Some subvolumes have been deleted from the source, but why
> does that matter? I am able to take a valid snapshot at this time and
> every snapshot ever taken continues to reside at the target backup
> destination (seemingly meaning that a parent subvolume can be found at
> the target).
> 
> This issue seems to make btrfs send-receive a very fragile backup
> solution. 

btrfs send/receive is not backup solution - it is low level tool that
does exactly what it is told to do. You may create backup solution that
is using btrfs send/receive to transfer data stream, but then do not
blame tool for incorrect usage.

To give better advice how to fix your situation you need to describe
your backup solution - how exactly you select/create snapshots.

I hope, instead, there is some knowledge I'm missing, that
> when learned, will make this a robust backup solution.
> 
> Thanks
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