[ #Office365 ] What is Fort Knox ?

In a few words, it’s a new way SharePoint (in Office 365 only at this time) is storing blobs directly to Microsoft Azure.


The above schema shows that’s it’s an evolutionary step beyond RBS which allow to save BLOB outside Content Databases.

Fort Knox allows to save BLOBs directly in Microsoft Azure and to benefit from any innovation available in the storage part of Azure.

Fort Knox was designed to handle the massive gross capacity seen on OneDrive deployment.

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RBS and Fort Knox are very similar but present key differences both from a security level but also from how the storage works. This allows to go beyond standard limits encountered with RBS today.
With RBS, all demands coming from WFE are handled by the SQL Server at the content database level.
So even if BLOB storage is externalized, the load is not really removed from the SQL server.


With Fort Knox, all demands coming from WFE  are handled by the SQL Server at the content databse level, but this is only to get the location of BLOB in Windows Azure. Then the WFE goes directly to Azure which allow a much better scalability than with RBS.


The other great difference between RBS and Fort Knox (hence the name) is about security.1°) Each document (and BLOB) is splitted in several fragments.
Each fragment is encrypted (with AES 256 bits encryption) with its own unique key. Each is stored on separated Azure containers. Theses Azure containers are generated on demand (this is from where infinite scale is coming).

There is one key store per environment (farm)  where keys for Azure containers are stored.

Each fragment is stored on one container. And

2°) The master key for the environment is then used to crypt the keys used to crypt the document shreds.
3°) This is stored in the content DB.

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So we have 3 elements :
o a content db which know where the shreds are and has the keys to read them. It needs the master key to be able to read them.o the key store with the master key but which don’t know where things are.o an Azure environment with a massive number of shreds, with no ability to read them or reconstruct the documents.


So a pirate who would gain access to one of the three environnements would not be able to get access to the data.

And as a supplementary protection, these keys are regenerated every day !

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Almost all this information is coming from SPC364 session (Give users all the storage they want without going broke) by Zach Rosenfield.

The details on Fort Knox is beginning at 23’ of the recording and slide 15.

Other informations are coming from SPC279 Secure, Reliable and Evergreen Service at Massive Scale: Lessons learned from Running SharePoint Online by Ben Canning

Last but not least using Azure storage allow to benefit from very interesting and cost effective features.
We should mention erasure coding which is a very efficient way to provide redundancy to storage. It provides the equivalent of 3 local  copies by using only 1,33 the intitial storage space.For more details on this you can have a look here : Erasure Coding in Windows Azure Storage
One last question that may arise is to know whether or not this new feature will be made available one day on SharePoint On prem version.
I didn’t find any hint on this.

A french version of this post is available here : [ #Office 365 ] What is Fort Knox ?  flag_of_france[1]


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