data lakehouse shortcuts copying data instead of creating symbolic link

[Anonymous]

I'm testing out fabric for a customer to see if it makes sense to offload some of our azure workloads onto fabric to bring it closer to the business users etc

I'm seeing something I didn't expect with the onelake lakehouse shortcuts

A shortcut according to this - https://learn.microsoft.com/en-us/fabric/onelake/onelake-shortcuts - means a symbolic link to the data

But it appears to have copied it all across into the autogenerated onelake adlsv2 account. Why did this happen? Does this mean we pay for storage twice? How does it stay in sync if it isn't a link?

[Anonymous]

A shortcut really is a symbolic link and data is not copied from the original location when you create a shortcut. You see the data in the Azure Storage Explorer (as well as in OneLake File Explorer and any other app that is able to connect to OneLake using ADLS Gen2 APIs/SDKs) because this data was virtualized.

Try the following experiment - create a shortcut to a container storing gigabytes or terabytes of data in ADLS Gen2 and check if you can immediately see and access the data using this shortcut. Or you can believe me/us (Microsoft) that the answer is - yes, you will be able to access the data immediately, because it's not copied and stays where it was before you created a shortcut.

I agree it's not easy to check how much data you really store in OneLake right now. Perhaps it would be useful to use some metadata to distinguish the data in OneLake being accessed via shortcuts from the data physically stored in OneLake. You can submit it as a feature idea here: https://aka.ms/fabricideas.