Best Practice 19.4 – Review backup strategy for improvements

When running SAP on AWS, you should evaluate your approach to backups and retention to optimize the costs associated with location, retention, and recovery.

Suggestion 19.4.1 – Evaluate the locations of your backups

Amazon S3 is the suggested long-term storage solution for your SAP system backups for its low cost, durability, and storage class options. To copy the data on your Amazon EBS volumes to Amazon S3, you can use point in time snapshots, integrated database tools, or direct API calls to transfer data.

Snapshots are incremental backups, which means that only the blocks on the device that have changed after your most recent snapshot are saved. This minimizes the time required to create the snapshot and saves storage costs by not duplicating data.

Database backup solutions require a knowledge of database state to ensure consistency. AWS provides an SAP HANA backup solution (AWS Backint Agent for SAP HANA) at no additional cost which integrates directly with Amazon S3. For other SAP supported databases, there are database vendors or third-party provided backup tools available which support backing up directly to Amazon S3.

For ad-hoc requirements or as a staging area, it might be necessary to first back up to Amazon EBS. For these use cases, an ST1 volume type is a low-cost HDD volume which provides throughput and performance characteristics suitable for backups. Selecting ST1 can reduce your overall storage costs when the need to back up the SAP database to disk is required.

If using Amazon EFS for backups, consider EFS-Infrequent Access. This storage class reduces storage costs for files that are not accessed every day. Amazon EFS One Zone-Infrequent Access is not recommended for backups due to the data only residing in one Availability Zone.

Suggestion 19.4.2 – Review and implement a retention policy for standard backups

To control costs, you need to implement a retention policy aligned with your business requirements that covers the storage services in use.

Amazon S3 offers a range of storage classes designed for different use cases with characteristics such as cost per GB, minimum storage duration charge, and retrieval fee (where applicable). Understanding the retention and access requirements for your backups will help determine which storage class is most suitable to meet your requirements.

S3 Lifecycle policies can be used to automatically transfer to a different storage class without any changes to your application. For example, backups with shorter retention periods might be better suited to S3 Standard than S3-IA or Amazon Glacier options due to the minimum storage duration charges and retrieval fees associated with these classes. Backups with longer retention periods such as monthly backups for audit purposes are better suited to S3-IA or Amazon Glacier dependent on the required retention period.

Amazon Data Lifecycle Manager can be used to automate the creation, retention, and deletion of EBS snapshots and EBS-backed AMIs.

Amazon EFS lifecycle management automatically manages cost-effective file storage for your file systems.

Suggestion 19.4.3 – Create a strategy for ad-hoc backups

Ad-hoc backups of a system or component might be required prior to a change or as a reference for system state at a particular point in time. When the required retention does not align with your standard lifecycle policy, you might need to adopt a separate schedule or process for ensuring that storage usage and deletion is cost effective for the individual requirements of that backup.

Suggestion 19.4.4 – Review backup setup against recovery approach

Backups are used to revert a system to a previous point in time and to guard against failure scenarios. Ensuring cost efficiency through a robust, but not excessive, use of backup storage requires that you review the recovery approach. Challenge assumptions on requirements for older more granular backups. Determine if these earlier backups would be required in the event of a recovery.

For example, it is a valid strategy to use both database and file system backups. However, if the primary mechanism for recovery is using database restore tools, there might be opportunities to optimize costs by reducing the retention or deleting snapshot backups for some volumes.