Re: 14Gb of space lost after distro upgrade on BTFS root partition (long thread with logs)

["Austin S. Hemmelgarn" <ahferroin7@gmail.com>]

On 2018-08-28 15:14, Menion wrote:
> You are correct, indeed in order to cleanup you need
> 
> 1) someone realize that snapshots have been created
> 2) apt-brtfs-snapshot is manually installed on the system
Your second requirement is only needed if you want the nice automated 
cleanup.  There's absolutely nothing preventing you from manually 
removing the snapshots.
> 
> Assuming also that the snapshots created during do-release-upgrade are 
> managed for auto cleanup
> 
> Il martedì 28 agosto 2018, Noah Massey <noah.massey@gmail.com 
> <mailto:noah.massey@gmail.com>> ha scritto:
> 
>     On Tue, Aug 28, 2018 at 1:25 PM Menion <menion@gmail.com
>     <mailto:menion@gmail.com>> wrote:
>      >
>      > Ok, I have removed the snapshot and the free expected space is
>     here, thank you!
>      > As a side note: apt-btrfs-snapshot was not installed, but it is
>      > present in Ubuntu repository and I have used it (and I like the idea
>      > of automatic snapshot during upgrade)
>      > This means that the do-release-upgrade does it's own job on BTRFS,
>      > silently which I believe is not good from the usability perspective,
> 
>     You are correct. DistUpgradeController.py from python3-distupgrade
>     imports 'apt_btrfs_snapshot', which I read as coming from
>     /usr/lib/python3/dist-packages/apt_btrfs_snapshot.py, supplied by
>     apt-btrfs-snapshot, but I missed the fact that python3-distupgrade
>     ships its own
>     /usr/lib/python3/dist-packages/DistUpgrade/apt_btrfs_snapshot.py
> 
>     So now it looks like that cannot be easily disabled, and without the
>     apt-btrfs-snapshot package scheduling cleanups it's not ever
>     automatically removed?
> 
>      > just google it, there is no mention of this behaviour
>      > Il giorno mar 28 ago 2018 alle ore 19:07 Austin S. Hemmelgarn
>      > <ahferroin7@gmail.com <mailto:ahferroin7@gmail.com>> ha scritto:
>      > >
>      > > On 2018-08-28 12:05, Noah Massey wrote:
>      > > > On Tue, Aug 28, 2018 at 11:47 AM Austin S. Hemmelgarn
>      > > > <ahferroin7@gmail.com <mailto:ahferroin7@gmail.com>> wrote:
>      > > >>
>      > > >> On 2018-08-28 11:27, Noah Massey wrote:
>      > > >>> On Tue, Aug 28, 2018 at 10:59 AM Menion <menion@gmail.com
>     <mailto:menion@gmail.com>> wrote:
>      > > >>>>
>      > > >>>> [sudo] password for menion:
>      > > >>>> ID      gen     top level       path
>      > > >>>> --      ---     ---------       ----
>      > > >>>> 257     600627  5               <FS_TREE>/@
>      > > >>>> 258     600626  5               <FS_TREE>/@home
>      > > >>>> 296     599489  5
>      > > >>>>
>     <FS_TREE>/@apt-snapshot-release-upgrade-bionic-2018-08-27_15:29:55
>      > > >>>> 297     599489  5
>      > > >>>>
>     <FS_TREE>/@apt-snapshot-release-upgrade-bionic-2018-08-27_15:30:08
>      > > >>>> 298     599489  5
>      > > >>>>
>     <FS_TREE>/@apt-snapshot-release-upgrade-bionic-2018-08-27_15:33:30
>      > > >>>>
>      > > >>>> So, there are snapshots, right? The time stamp is when I
>     have launched
>      > > >>>> do-release-upgrade, but it didn't ask anything about
>     snapshot, neither
>      > > >>>> I asked for it.
>      > > >>>
>      > > >>> This is an Ubuntu thing
>      > > >>> `apt show apt-btrfs-snapshot`
>      > > >>> which "will create a btrfs snapshot of the root filesystem
>     each time
>      > > >>> that apt installs/removes/upgrades a software package."
>      > > >> Not Ubuntu, Debian.  It's just that Ubuntu installs and
>     configures the
>      > > >> package by default, while Debian does not.
>      > > >
>      > > > Ubuntu also maintains the package, and I did not find it in
>     Debian repositories.
>      > > > I think it's also worth mentioning that these snapshots were
>     created
>      > > > by the do-release-upgrade script using the package directly,
>     not as a
>      > > > result of the apt configuration. Meaning if you do not want a
>     snapshot
>      > > > taken prior to upgrade, you have to remove the apt-btrfs-snapshot
>      > > > package prior to running the upgrade script. You cannot just
>     update
>      > > > /etc/apt/apt.conf.d/80-btrfs-snapshot
>      > > Hmm... I could have sworn that it was in the Debian repositories.
>      > >
>      > > That said, it's kind of stupid that the snapshot is not trivially
>      > > optional for a release upgrade.  Yes, that's where it's
>     arguably the
>      > > most important, but it's still kind of stupid to have to remove a
>      > > package to get rid of that behavior and then reinstall it again
>     afterwards.
>