Here is the question of the day. It's dealing with different types of backups. First, let's start with what we know.
- A Full backup backs up the files, then resets the archive bits to off so that it knows they've been backed up.
- An Incremental backup backs up the files with the archive bit set to on (meaning the file has been changed), then resets the bit to off for each file that has had changes.
- A Differential backup backs up all the files where the archive bit it set to on, but doesn't reset it to off, meaning it will back up everything where the bit is set to on, including files it has already backed up in any previous differential backups since the last full backup (since differentials do not reset the bit to off).
- Any file changes sets the bits to on. So either an incremental or differential will back up the changed files.
So here's the scenario:
- I do a full backup, change files, then do an incremental (which will backup the files, then change the bits back to off)
- I change no files over the next 24 hours, then I do a differential backup.
So here are the questions:
- How will the differential recognize the difference between the full and incremental backups because the bits are set to off for both cases?
- Will it copy since the last full backup or the last incremental?
