SQL Interview: 27 Copy only backups in SQL Server

This is a post in the SQL Interview series. These aren’t trick or gotcha questions, they’re just questions designed to scope out a candidate’s knowledge around SQL Server and Azure SQL Database.

Section: Administration Level: Intro

Question:

You need to take an additional backup copy of a database to send to another site. You are considering using the Copy Only backup option.

What exactly is different about a Copy Only backup, compared to a Full backup?

Answer:

A Copy Only backup does not clear the extent map that is used to track modified extents for Differential backups.

2025-03-17