Log shipping - AWS Prescriptive Guidance

Log shipping

Log shipping lets you automatically send transaction log backups from a primary database instance to one or more secondary databases (also known as warm standby) on separate DB instances. Log shipping uses SQL Server Agent jobs to automate the process of backing up, copying, and applying the transaction log backups. Although log shipping is typically considered a disaster recovery feature, it can also provide high availability by allowing secondary DB instances to be promoted if the primary DB instance fails. If your RTO and RPO are flexible, or your databases aren’t considered highly mission-critical, consider using log shipping to provide better availability for your SQL Server databases.

Log shipping increases the availability of databases by providing access to secondary databases to use as read-only copies of the primary database when needed. You can configure a lag delay (a longer delay time) during which you can recover accidentally changed data on the primary database before these changes are shipped to the secondary database.

We recommend running the primary and secondary DB instances in separate Availability Zones, and deploying a monitor instance to track all the details of log shipping. Backup, copy, restore, and failure events for a log shipping group are available from the monitor instance. A log shipping configuration doesn’t automatically fail over from the primary server to the secondary server. However, any of the secondary databases can be brought online manually if the primary database becomes unavailable.

Log shipping is often used as a disaster recovery solution but also can be used as a high availability solution, depending on your application requirements. Use log shipping when:

  • You have flexible RTO and RPO requirements. Log shipping provides an RPO of minutes, and an RTO of minutes to hours.

  • You do not need an automatic failover to the secondary database.

  • You want to read from the secondary database, but you don’t require readability during a restore operation.

For more information about log shipping, see the Microsoft SQL Server documentation.