This first came up during my onboarding with Pure Storage. Anthony Nocentino (b|t) taught me that a SQL Server backup file is a byte-for-byte copy of your data, as materialized in SQL Server MDF files (assuming no backup compression or backup encryption). And that would make sense – how else would SQL Server store a copy of your data in a backup file? It does not make sense for SQL Server to alter your data when it writes it down to a backup file (again, with NO backup compression/encryption) – that’s a waste of compute and effort.
Well, I had a conversation with someone who was unclear about that assertion. I tried some Google-fu to present some supporting materials, but could not actually find any documentation, official or otherwise, to back it up. So here we are.
Click through to dive into a backup file with Andy.