The latest preview resource coming to Azure is Immutable Storage Accounts - meaning write once read many (WORM). The best part is that this feature will prevent deletion or update of written files. This will be appealing to financial organizations, or organizations guided or impacted by regulations that might require permanent storage of files.
The ability to configure storage to keep data forever and prevent deletion by any users (including administrators) is both a blessing and a curse - while the cost of keeping data long term can quickly get expensive, not to mention require careful scrutiny so that the storage of these files only happens when it is absolutely necessary. Keeping data for the sake of keeping data is a bad practice all the way around. Only keep data that is required and only keep it for the required period of time... once the timeframe for a file passes, age the file out.
Thankfully, Immutable storage supports that as well. This way, when your documentation is older than seven years it will age out and pretty much force an update; in addition, the initial file cannot be updated so the old version of the documentation will be around unchanged until it ages out - this way, if someone needs it for testing or reference it has not changed.
I realize that the documentation example is not the best for something sitting around regulatory rules, but it is a straightforward concept for file aging.
The details of Immutable Storage preview can be found at https://azure.microsoft.com/en-us/blog/microsoft-azure-launches-tamper-proof-azure-immutable-blob-storage-for-financial-services/
What about legal hold?
Legal Hold is also available as part of immutable storage - keeping data for litigation to ensure it does not get altered or deleted is almost a requirement in the state of the world today - using a policy to ensure that this data is placed in immutable storage and an aging to keep it as necessary and remove it when no longer required.
Immutable storage is definitely something that all Azure users should at least learn about to become familiar with it as it might be a feature that your business relies on going forward.
More on this coming once I have had a chance to mess around with it a bit.