SQL Server - How does Always On in a shared nothing config maintain transaction durability during a failover? I've been reading up on Always On, and I was wondering how transactional durability is maintained during a failover when using a shared nothing configuration.

The only things I can find on google talk about log shipping, but this would mean that if a failover occurs in-between log restores, then some transactions could be lost.
You use synchronous commit mode. This means transactions committed on the primary will also be committed on the secondary (over your network). So, if you failover during a transaction it will be rolled back when the secondary is brought online after recovery.

https://msdn.microsoft.com/en-us/library/ff877931.aspx


  Synchronous-commit mode protects your data by requiring the data to be synchronized between two places, at the cost of somewhat increasing
  the latency of the transaction.