dotnet restore takes too long on VSTS

Question

I have asp.net core 2.0 app, which references Microsoft.AspNetCore.All metadata package

<PackageReference Include="Microsoft.AspNetCore.All" Version="2.0.0" />

and I have following build in VSTS which I build using hosted build agent.

Why it always takes min 95 seconds to restore the packages? I thought that

1. Microsoft.AspNetCore.All packages are cached in ".NET Core runtime store" so they don't have to be restored.
2. When I restore the packages once, they don't have to be be restored again in every build, since they are cached.

Why is dotnet restore so slow in VSTS?

Edit: Vote for better VSTS build performance here: https://visualstudio.uservoice.com/forums/330519-visual-studio-team-services/suggestions/32044321-improve-hosted-build-agent-performance

Answer 1

From the Microsoft Docs on Hosted Agents:

Capabilities and limitations

Hosted agents:

• Run as a service.
• Have the above software. You can also add software using our tool installers.
• Provide 10GB of storage.

Hosted agents do not offer:

• Interactive mode.
• Administrator privileges.
• The ability to log on.
• The ability to drop artifacts to a UNC file share.
• The ability to run XAML builds.
• Potential performance advantages that you might get by using private agents which might start and process builds faster. Learn more

If our hosted agents don't meet your needs, then you can deploy your own private agents.

Long and short, using the hosted agents, what you get is what you get. If it's not fast enough for you or doesn't do something else you'd like (such as caching of NuGet packages), then your recourse is to create your own private build agent.