[arch-general] btrfs/snapper hook for pacman 5.0?

[Elmar Stellnberger]

Am 2016-02-02 um 14:53 schrieb Karol Babioch:
> Hi,
>
> Am 02.02.2016 um 14:15 schrieb Elmar Stellnberger:
>> However you may implement this feature please make sure that it takes
>> care of the availabel disk space! Most people do only have limited space
>> on their root partition and by making numerous snapshots your hard drive
>> will be clobbered soon. Besides this the feature should stop
>> automatically or ask for elder snapshots to be deleted before the max.
>> drive fill reaches a certain percentage (f.i. 80%). As soon as your root
>> partition gets filled by 100% you may not even be able to boot from it.
>
> The good thing is that snapper is taking care of most of these issues.
> It will automatically remove snapshots (according to your configuration).
>
> pacman is also checking for available disk space before doing the upgrade.
>
> So for all practical means the combination of both should be good enough.
>
> Best regards,
> Karol Babioch
>

Hi all,

   The problem about it is that when a new snapshot is created no 
additional disk space becomes consumed immediately. Only on change of 
the given files a possibly huge amount of disk space can get allocated 
by Copy On Write. The problem about it is that the update tool does not 
know that changing one byte in file X will result in a full copy of that 
file structure and block.
   I am saying this because I have already run into the 100% disk space 
consumed issue with snapper and openSUSE a couple of years ago.

Elmar