Does FULL and LOG backup sequence affect backup size?
Posted on 2010-11-16
This is an advanced question about SS 2005 and SS 2008 backups. When backing up a database that has a FULL recovery model, I perform both a FULL and a LOG backup every day, once a day. I want to understand any differences between doing the log backup first versus doing the full backup first. Using N to represent the most recent backup and N-1 to represent the backup just prior to the most recent backup ...
1. How will the sequence affect the size of the backup files?
2. Will either sequence prevent me from restoring the N log backup on top of the N-1 full backup (restored without recovery, of course) to roll the database forward to a specific point in time that is between the N-1 backup and the N backup? In other words, will either sequence require that I apply both the N and N-1 log backups to a restored N-1 full backup?
3. Is there a difference in the amount of truncation in the log with either sequence?
4. Are there any other differences that I should be aware of?