Re: [PATCH v3 0/5] Improving apt cache

["Roberto A. Foglietta" <roberto.foglietta@gmail.com>]

On Mon, 30 Jan 2023 at 09:45, Moessbauer, Felix
<felix.moessbauer@siemens.com> wrote:
>
> On Fri, 2023-01-20 at 08:31 +0100, Uladzimir Bely wrote:
> > Currently, apt cache (e.g. `var/cache/apt/archives`) import and
> > export
> > functions are not optimal. Multiple files are copied from global
> > DL_DIR to package WORKDIR, increasing disk IO and space needed.
> >
> > Also, various chroots (bootstrap, buildchroot, sbuild chroot) include
> > their apt caches to sstate cache files.
> >
> > This patchset switches to hardlinks instead of copies and removes apt
> > cache from bootstrapped images ans sstate caches.
>
> I just saw that this pattern does NOT work in case the cache is on a
> different filesystem. This unfortunately is the case for all CI systems
> with locally mounted caches, as well as for kas-container builds with
> DL_DIR outside the KAS_WORK_DIR.
>
> In short: This breaks a LOT of use-cases.
> I'm really sorry that we only found that by know.
> But we definitely need a different solution.
>
> Example output:
> 2023-01-30 08:38:51 - INFO     - | ln: failed to create hard link
> '/builds/iiot-edge-device/foo/meta-iot2050-pg2-
> foo/build/tmp/work/debian-bullseye-amd64/isar-bootstrap-target/1.0-
> r0/rootfs/var/cache/apt/archives/gcc-arm-linux-gnueabihf_4%3a10.2.1-
> 1_arm64.deb' => '/local-cache/meta-iot2050-pg2-
> foo/downloads/deb/debian-bullseye/gcc-arm-linux-gnueabihf_4%3a10.2.1-
> 1_arm64.deb': Invalid cross-device link
>

One more thing: as shown to Uladzimir, as long as the source of two
different mount points (not filesystems) exists on the same
filesystem, then lp -P complains but for some reason it works. I do
not grant that it works in any case but it works enough for which a
2>/dev/null makes the building complete and no one notices. So, if it
does not build, that's an issue. If it completes the build despite the
stderr messages, we are lucky. However, if confirmed - this weird
behaviour - is out of the standard, so being lucky is not enough in
the long run.

Best regards, R-