Artifact tarball size limits

[mthalman]

I'd like to get feedback from the community on whether there are any size limitations for consuming the source build artifacts tarball. Please reply if you are aware of any size limits in consuming this file.

@dotnet/distro-maintainers

[omajid]

We have (had?) an internal system limitation where the total size of all "sources" to build can not exceed 4GiB. In the past (eg, .NET Core 3.1), when trying to bootstrap a new version of .NET we would often hit this limit and try and deal with workarounds. The limit includes the source tarball, previously-source-built-artifacts, and the prebuilt-SDK, multiplied for all architectures we want to build.

For .NET 10 Preview size, this is how the sizes look on my system:

445M dotnet-10.0.0-preview.5.25277.114.tar.gz
4.0K dotnet-10.0.0-preview.5.25277.114.tar.gz.sig
1.2G dotnet-prebuilts-10.0.100-preview.5.25265.107-arm64.tar.gz
1.2G dotnet-prebuilts-10.0.100-preview.5.25265.107-x64.tar.gz
376M dotnet-prebuilts-10.0.100-preview.5.25277.114-ppc64le.tar.gz
380M dotnet-prebuilts-10.0.100-preview.5.25277.114-s390x.tar.gz

The dotnet-prebuilt archive contains the source-built artifacts and the SDK, for each architecture:

$ tar tf dotnet-prebuilts-10.0.100-preview.5.25265.107-arm64.tar.gz
dotnet-prebuilts-10.0.100-preview.5.25265.107-arm64/
dotnet-prebuilts-10.0.100-preview.5.25265.107-arm64/Private.SourceBuilt.Artifacts.Bootstrap.tar.gz
dotnet-prebuilts-10.0.100-preview.5.25265.107-arm64/dotnet-sdk-10.0.100-preview.5.25265.107-linux-arm64.tar.gz
$ tar tf dotnet-prebuilts-10.0.100-preview.5.25265.107-x64.tar.gz
dotnet-prebuilts-10.0.100-preview.5.25265.107-x64/
dotnet-prebuilts-10.0.100-preview.5.25265.107-x64/Private.SourceBuilt.Artifacts.Bootstrap.tar.gz
dotnet-prebuilts-10.0.100-preview.5.25265.107-x64/dotnet-sdk-10.0.100-preview.5.25265.107-linux-x64.tar.gz
$ tar tf dotnet-prebuilts-10.0.100-preview.5.25277.114-ppc64le.tar.gz
dotnet-prebuilts-10.0.100-preview.5.25277.114-ppc64le/
dotnet-prebuilts-10.0.100-preview.5.25277.114-ppc64le/Private.SourceBuilt.Artifacts.10.0.100-preview.5.25277.114.linux-ppc64le.tar.gz
dotnet-prebuilts-10.0.100-preview.5.25277.114-ppc64le/dotnet-sdk-10.0.100-preview.5.25277.114-linux-ppc64le.tar.gz

And assembling into the final "source" archive produces:

3.5G dotnet10.0-10.0.100~preview.5.25277.114-0.4.fc42.src.rpm

[dviererbe]

As far as I know, the Ubuntu archive does not have a size limit.

But there are other limiting factors:

• Uploading a tarball can timeout if the upload takes too long. Therefore the maximum tarball size is practically limited by the upload speed to the Ubuntu archive. I remember that this was actually an issue with .NET 6 and ~2.0 GiB tarballs when the infra was under high load.
• The default Launchpad PPA size is 8.0 GiB. If the tarball size is larger, it makes testing for us more difficult, because we would need to ask the Launchpad team to increase the limit for every PPA we create during testing.

[dviererbe]

Oh, I just noticed that I misread the question. It's about consuming the binaries not about uploading the source.

As far as I know there is also no limit in the publishing size to the Ubuntu archive or a Launchpad PPA (funnily enough you can endlessly exceed the PPA limit, e.g. our backports PPA uses 15.8 GiB of 8.0 GiB).

We noticed in the past that sometimes the size of the artifacts tarball can cause Cannot write: No space left on device errors of our autopkgtest runners, but if we should run into this problem again, we could probably ask to increase the size of our runners.

[mthalman]

Related: #5280

[corngood]

The public build infrastructure for nix has a size limit on derivation outputs, and I believe it's 3GiB.

The packed tarball is one of those outputs. The output of a VMR build also has to be within that limit. It's currently 2.2GiB, of which about half is Private.SourceBuilt.Artifacts, which is unpacked at that point.

I think we'll be okay unless it grows by ~50%.