backupsql servertransaction-log
If Full backup is scheduled for every Sunday at 12 pm and differential back up is scheduled for for every 6 hours and transaction log backup is scheduled for every 15 minutes.
My problem is what is the use of differential backup every 6 hours if we are taking a transaction log backup every 15 minutes? Is it enough to have only full backup and transaction log backup only ?
Thank you
As you can see in this table, there is no conflict between Full backup and Log backup. They can occur at same time, and, when log backup completes, log will not be cleaned until full backup (or diff backup) completes.
Not all administrative tasks are allowed to run concurrently. In the table below, a black circle indicates two operations that cannot run in a database at the same time.
References:
At the very least you need to consider differential backups. Unless copy-only on the full is used, your next diff backup will be off. Copy-Only Backups:
Copy-only full backups (all recovery models) A copy-only backup cannot serve as a differential base or differential backup and does not affect the differential base.
The only difference between full and full-copy is that full-copy does not break the differential chain. Neither of them breaks the log chain as neither of them truncates the log file.
Best Answer
Differential backup is used to decrease the Recovery time object(RTO), it gives you facility of restoring backups quickly. Differential backup includes all the changes made since last full backup, or full backup which started the differential chain. Differential backup is not affected by log backup so in event of disaster you would have to restore(in your case)