Cache fails to save files correctly when using archive.ubuntu.com

[Da Xue]

After priming the cache, turning on offline mode results in "503 Unable to download in offline mode" errors because the cached files do not match in size in the .head files.

[Da Xue (daxue)]

It's a problem due to archive.ubuntu.com instead of us.archive.ubuntu.com. It's simply not liking it.

To get around the issue, delete your existing cache, and set the us.archive.ubuntu.com for all references instead of just archive.ubuntu.com.

[Rolf Leggewie (r0lf)]

acng does not have an offline mode, I suspect you are referring to apt-cacher. Generally, your problem is not well-described and thus hard to reproduce.

[Eduard Bloch (edi-gmx)]

It does have offline mode (has been there almost from the start). What I don't understand is the exact action behind "priming the cache". The explanation also does not make sense - in offline mode, it wouldn't attempt to make an online connection so it would not know that the size differs.

If I find some spare time, I could test the repro steps from #1 in an Ubuntu chroot but don't expect much.

[Da Xue (daxue)]

I use it mainly for caching packages and doing offline installs from the repository. When I use archive.ubuntu.com, it only does partial saves of the files. I haven't had a chance to debug more thoroughly.

Steps to replicate:

Set archives to archive.ubuntu.com
Turn OFF offline-mode
Prime cache by installing few packages
Turn ON offline-mode
Try to install the same packages on a different instance

It's alleviated when you use us.archive.ubuntu.com so it's not a blocker.

Hope this helps.

[Da Xue (da-t)]

Rolf, please move this bug back to apt-cacher-ng. This is not an apt-cacher bug. There is indeed a bug where the the .head file provides the content size and the regular files don't get cached properly.