What happens when full backup, differential backup and log backup schedules collide

backupsql server

Suppose I have configured full backup for every Sunday 1AM, differential backup every day at 1AM and log backups every hours from 12AM.

So, every day the differential and log backups collide at 1AM.

On Sunday all 3 backups collide at 1AM.

How does SQL server backups work under this scenario?

Best Answer

It's possible to take a full backup or a differential backup, and log backups concurrently of the same database. However, a full backup and differential backup cannot run concurrently as both will attempt to get a BULKOP_BACKUP_DB lock on the database. This means whichever receives the lock first gets to run first. The other will run after the previous finishes.

This can be exacerbated if the database belongs to an Availability Group and backups are being taken on multiple replicas.

You shouldn't have any issues, other than typical blocking that will happen for the duration of the blocking request. Whether or not this is truly a problem is up to you in your specific environment.