Optimize SQL Server backup strategies - AWS Prescriptive Guidance

Optimize SQL Server backup strategies

Overview

Most organizations are looking for the right solution to safeguard their data on SQL Server on Amazon EC2 to meet their current requirements for Recovery Point Objective (RPO), the maximum acceptable amount of time since the last backup, and Recovery Time Objective (RTO), the maximum acceptable delay between the interruption of service and restoration of service. If you're running SQL Server on EC2 instances, you have multiple options for creating backups of your data and restoring your data. Backup strategies for safeguarding data for SQL Server on Amazon EC2 include the following:

You have the following storage options for database-level native backup:

This section does the following:

  • Highlights features to help you save on storage space

  • Compares the costs between different backend storage options

  • Provides links to in-depth documentation to help implement these recommendations

Server-level backup using VSS-enabled snapshots

A VSS-enabled snapshots architecture uses the AWS Systems Manager Run Command to install the VSS agent on your SQL Server instances. You can also use the Run Command to invoke the entire workflow of flushing operating system and application buffers to the disk, pausing I/O operations, taking a point-in-time snapshot of the EBS volumes, and then resuming I/O.

This Run Command creates automated snapshots of all EBS volumes attached to a target instance. You also have the option to exclude the root volume, because user database files are usually stored on other volumes. In case you stripe multiple EBS volumes to create a single file system for SQL Server files, Amazon EBS also supports crash-consistent multivolume snapshots using a single API command. For more information about application-consistent VSS-enabled EBS snapshots, see Create a VSS application-consistent snapshot in the Amazon EC2 User Guide for Windows Instances.

The following diagram shows an architecture for server-level backup using VSS-enabled snapshots.


                                        VSS-enabled snapshots architecture

Consider the following benefits of using VSS-enabled snapshots:

  • The first snapshot of a DB instance contains the data for the full DB instance. Subsequent snapshots of the same DB instance are incremental, which means that only the data that has changed after your most recent snapshot is saved.

  • EBS snapshots provide point-in-time recovery.

  • You can restore to a new SQL Server EC2 instance from a snapshot.

  • If an instance is encrypted using Amazon EBS or if a database is encrypted in the instance using TDE, that instance or database is automatically restored with the same encryption.

  • You can copy your automated cross-Region backups.

  • When you restore an EBS volume from a snapshot it becomes immediately available for applications to access it. This means that you can immediately bring SQL Server online after restoring one or more of its underlying EBS volumes from snapshots.

  • By default, restored volumes fetch underlying blocks from Amazon S3 the first time an application tries to read them. This means that there can be a lag in performance after an EBS volume is restored from a snapshot. The volume eventually catches up with the nominal performance. However, you can avoid that lag by using fast snapshot-restore (FSR) snapshots.

  • You can use lifecycle management for EBS snapshots.

Consider the following limitations of using VSS-enabled snapshots:

  • You can’t perform cross-Region point-in-time recovery with an encrypted snapshot for a SQL Server instance.

  • You can’t create an encrypted snapshot of an unencrypted instance.

  • You can’t restore an individual database because the snapshot is taken at the EBS volume level.

  • You can’t restore the instance to itself.

  • A snapshot of the DB instance must be encrypted by using the same AWS Key Management Service (AWS KMS) key as the DB instance.

  • Storage I/O is suspended for a fraction of a second (approximately 10 milliseconds) during the snapshot backup process.

SQL Server backup using AWS Backup

You can use AWS Backup to centralize and automate data protection across AWS services. AWS Backup offers a cost-effective, fully managed, policy-based solution that simplifies data protection at scale. AWS Backup also helps you support your regulatory compliance obligations and meet your business continuity goals. Together with AWS Organizations, AWS Backup enables you to centrally deploy data protection (backup) policies to configure, manage, and govern your backup activity across your organization’s AWS accounts and resources.

The following diagram shows the architecture of a backup and restore solution for SQL Server on EC2 by using AWS Backup.


                                            AWS Backup architecture

Consider the following benefits of backing up SQL Server by using AWS Backup:

  • You can automate backup scheduling, retention management, and lifecycle management.

  • You can centralize your backup strategy across your organization, spanning multiple accounts and AWS Regions.

  • You can centralize monitoring your backup activity and alerting across AWS services.

  • You can implement cross-Region backups for disaster recovery planning.

  • The solution supports cross-account backups.

  • You can perform secure backups with secondary backup encryption.

  • All backups support encryption by using AWS KMS encryption keys.

  • The solution works with TDE.

  • You can restore to a specific recovery point from the AWS Backup console.

  • You can back up an entire SQL Server instance, which includes all SQL Server databases.

Database-level backup

These approaches use native Microsoft SQL Server backup functionality. You can take backups of individual databases on the SQL Server instance and restore an individual database.

Each of these options for native SQL Server backup and restore also support the following:

  • Compression and multiple-file backup

  • Full, differential, and T-log backups

  • TDE-encrypted databases

SQL Server native backup and restore to Amazon S3

SQL Server on EC2 supports native backup and restore for SQL Server databases. You can take a backup of your SQL Server database and then restore the backup file to an existing database or to a new SQL Server EC2 instance, Amazon RDS for SQL Server, or an on-premises server.

Storage Gateway is a hybrid cloud storage service that provides on-premises applications with access to virtually unlimited cloud storage. You can use AWS Storage Gateway to back up your Microsoft SQL Server databases directly to Amazon S3, reducing your on-premises storage footprint and using Amazon S3 for durable, scalable, and cost-effective storage.

The following diagram shows the architecture of a native backup and restore solution that uses Storage Gateway and Amazon S3.


                                                Storage Gateway and Amazon S3 architecture

Consider the following benefits of using native SQL Server backup with Storage Gateway:

  • You can map a storage gateway as a Server Message Block (SMB) file share on the EC2 instance and send the backup to Amazon S3.

  • The backup goes directly to the S3 bucket or through the Storage Gateway file cache.

  • Multiple-file backups are supported.

Consider the following limitations of native backup using Storage Gateway:

  • You must set up backup and restore for each individual database.

  • You must manage the Amazon S3 lifecycle policy for the backup files.

For more information about how to set up Storage Gateway, see the Store SQL Server backups in Amazon S3 using AWS Storage Gateway post on the AWS Blog.

SQL Server native backup to EBS volumes

You can take a native backup of your SQL Server database and store the file in an Amazon EBS volume. Amazon EBS is a highly performant block storage service. EBS volumes are elastic, which supports encryption. They can be detached and attached to an EC2 instance. You can back up SQL Server on an EC2 instance on the same EBS volume type or on a different EBS volume type. One advantage of backing up to a different EBS volume is cost savings.

The following diagram shows the architecture of a native backup to an EBS volume.


                                                EBS volume architecture

Consider the following benefits of using SQL Server native backup to EBS volumes:

  • You can take backups of individual databases on a SQL Server EC2 instance and restore an individual database instead of having to restore the complete instance.

  • Multiple-file backups are supported.

  • You can schedule backup jobs by using SQL Server Agent and the SQL Server job engine.

  • You can get performance benefits through your hardware choices. For example, you can use st1 storage volumes to achieve higher throughput.

Consider the following limitations of using native backup to EBS volumes:

  • You must manually move backups to Amazon S3 from the EBS volume.

  • For large backups, you must manage disk space on Amazon EC2.

  • On the EC2 instance, Amazon EBS throughput can be a bottleneck.

  • Additional storage is required to store backups on Amazon EBS.

SQL Server native backup to Amazon FSx for Windows File Server

Amazon FSx for Windows File Server is a fully managed native Windows file system that offers up to 64 TB of storage designed to deliver fast, predictable, and consistent performance. AWS introduced native support for Multi-AZ file system deployments on FSx for Windows File Server. Native support makes it easier to deploy Windows file storage on AWS with high availability and redundancy across multiple Availability Zones. AWS also introduced support for SMB Continuously Available (CA) file shares. You can use FSx for Windows File Server as backup storage for a SQL Server database.

The following diagram shows the architecture of a native SQL Server backup to FSx for Windows File Server.


                                                FSx for Windows File Server backup architecture

Consider the following benefits of using native SQL Server backup to FSx for Windows File Server:

  • You can back up your SQL Server database to an Amazon FSx file share.

  • You can take backups of individual databases on a SQL Server instance and restore an individual database instead of having to restore the complete instance.

  • Multi-part backups are supported.

  • You can schedule backup jobs by using SQL Server Agent and the job engine.

  • The instances have higher network bandwidth compared to Amazon EBS.

Consider the following limitations of using native SQL Server backup to FSx for Windows File Server:

  • You must manually move backups to Amazon S3 from Amazon FSx by using AWS Backup or AWS DataSync.

  • Large backups might require additional overhead for disk space management on Amazon FSx.

  • EC2 instance network throughput can be a bottleneck.

  • Additional storage is required to store backups on FSx for Windows File Server.

SQL Server backup to Amazon FSx for NetApp ONTAP

Snapshots with FSx for ONTAP are always crash consistent, but they require you to quiesce (or pause the I/O of) your database in order to create an application-consistent snapshot. You can use NetApp SnapCenter (an orchestration tool with plug-ins for specific applications, including SQL Server) with FSx for ONTAP to create application-consistent snapshots and protect, replicate, and clone your databases at no additional cost.

NetApp SnapCenter

NetApp SnapCenter is a unified platform for application-consistent data protection. SnapCenter refers to snapshots as backups. This guide adopts that same naming convention. SnapCenter provides a single pane of glass for managing application-consistent backups, restores, and clones. You add a SnapCenter plug-in for your specific database application to create application-consistent backups. The SnapCenter plug-in for SQL Server provides the following functionality that simplifies your data protection workflow.

  • Backup and restore options with granularity for full and log backups

  • In-place restore and restore to an alternate location

For more information about SnapCenter, see the Protect your SQL Server workloads using NetApp SnapCenter with Amazon FSx for NetApp ONTAP post on the AWS Storage Blog.

Cost optimization for backups

The following options can help you reduce the cost of storing SQL Server backups on AWS.

  • Enable SQL Server compression during the creation of the backup file and send the smallest possible file to the storage. For example, a 3:1 compression ratio indicates that you are saving about 66 percent on disk space. To query on these columns, you can use the following Transact-SQL statement: SELECT backup_size/compressed_backup_size FROM msdb..backupset; .

  • For backups going to S3 buckets, enable the Amazon S3 Intelligent-Tiering storage class to reduce storage costs by 30 percent. 

  • For backups going to FSx for Windows File Server or FSx for ONTAP, use a single Availability Zone for 50 percent cost savings (as compared to using multiple Availability Zones). For pricing information, see Amazon FSx for Windows File Server Pricing and Amazon FSx for NetApp ONTAP Pricing.

  • The most efficient option for SQL Server 2022 is direct backup to Amazon S3. You can save additional costs by avoiding Storage Gateway.

Benchmark test results for backups

This section compares the following options from a cost and performance point of view for a sample 1 TB database, based on the results of performance benchmark testing on the backup solutions covered in this guide.

  • EC2 instance specification – r5d.8xlarge with Windows Server 2019 and SQL Server 2019 Developer edition

  • Database specification – 1 TB in size with TDE disabled

The tests were performed with an r5d.8xlarge instance and 1 TB SQL Server database as the source. The source system was configured according to best practices, and the source database contained four data files (250 GB each) and one log file (50 GB) spread across separate gp3 volumes. The SQL Server native BACKUP command includes writing to 10 backup files, using compression to optimize backup performance and reduce the amount of data sent across the network and written to the target. In all test cases, storage performance was the bottleneck.

There is an almost endless variety of possible configurations for these types of test. This test focused on optimizing for performance, cost, scalability, and real-world use cases. The following table shows the performance metrics that were captured for the backup target options.

Backup options

Level

Run duration (Appx)

Backup rate

Cost USD per month*

Native backup to local EBS st1 HDD, 2 TB

Database

00:30:46 min

554.7 Mbps

$92.16

Native backup to local EBS SSD gp3, 2 TB

Database

00:22:00 min

512 Mbps

$193.84

Native backup to FSx for Windows File Server HDD, 2 TB @512 Mbps throughput

Database

00:20:58 min

814.0 Mbps

$1,146

Native backup to FSx for Windows File Server SSD, 2 TB @512 Mbps throughput

Database

00:20:00 min

814.0 Mbps

$1,326

Native backup to S3 File Gateway m6i.4xlarge (16 vCPU, 64 GB) with 2 TB gp3

Database

00:23:20 min

731.5 Mbps

$470.42

EBS VSS snapshot

EBS volume

00:00:02 sec

00:00:53 sec

N/A snapshot

$51

AWS Backup (AMI backup)

AMI

00:00:04 sec

00:08:00 min

N/A snapshot

$75

Native SQL Server backup directly to Amazon S3 (SQL Server 2022)

Database

00:12:00 min

731.5 Mbps

First 50 TB / Month, $0.023 per GB $23.55 per month

Native backup to FSx for NetApp ONTAP (using SnapCenter)

Database

$440.20

The preceding table assumes the following:

  • Data transfer and Amazon S3 costs are not included.

  • Storage price is included in instance pricing.

  • The costs are based in the us-east-1 Region.

  • Throughput and IOPS grow by 10 percent with multiple backups that have an overall rate of change of 10 percent over the month.

The test results show that the fastest option is a native SQL Server database backup to FSx for Windows File Server. A backup to Storage Gateway and locally attached EBS volumes is the more cost-efficient option but has slower performance. For server-level backups (AMI), we recommend using AWS Backup for optimal performance, cost, and manageability.

Cost optimization recommendations

Understanding the possible solutions for backing up SQL Server on Amazon EC2 is key to safeguarding your data, ensuring that you meet your backup needs, and putting a plan in place to recover from critical events. The different ways to back up and restore your SQL Server instances and databases explored in this section can help you devise a backup and restore strategy that protects your data and meets your organization's requirements.

This section covers the following backup options:

  • Compression

  • Amazon S3 Intelligent-Tiering

  • Single Availability Zone

  • Backup to URL

The guidance provided for each of these options is high level. If you wish to implement any of these recommendations in your organization, we recommend that you reach out to your account team. The team can then engage with a Microsoft Specialist SA to lead the conversation. You can also reach out by emailing optimize-microsoft@amazon.com.

In summary, we recommend the following:

  • If you're using SQL Server 2022, then backing up to Amazon S3 is the most cost-efficient option.

  • If you're using SQL Server 2019 and earlier SQL Server editions, consider backing up to Storage Gateway backed by Amazon S3 as the most cost-efficient option.

Compression

The goal of compression is to have less storage consumed by each backup, which is beneficial for various storage options. You must enable compression for a SQL Server backup at the level of the SQL Server instance. The following example shows how to add the compression keyword with a backup database:

BACKUP DATABASE database_name TO DISK WITH COMPRESSION (ALGORITHM = QAT_DEFLATE)

Amazon S3 Intelligent-Tiering

For backups going to Amazon S3 buckets, you can enable Amazon S3 Intelligent-Tiering as your Amazon S3 File Gateway storage class. This can reduce storage costs by up to 30 percent. You then mount File Gateway to your SQL servers by using an SMB file share that can be integrated with your Active Directory domain. This provides you with access control for your share, the ability to leverage existing service accounts, and access to Amazon S3 using a common Microsoft focused file protocol. For accounts that might not have direct connectivity to a domain controller, you can use the Active Directory Connector to facilitate communication with Active Directory on-premises or in the cloud. To configure the Active Directory settings on the gateway, you must specify the Active Directory Connector IPs for the domain controller to proxy requests to Active Directory.

The following diagram shows an architecture for a solution based on S3 Intelligent-Tiering.


                                                    S3 Intelligent-Tiering architecture

By default, the backup files written to the S3 bucket use the Standard tier. To convert the backup files from the Standard tier to S3 Intelligent-Tiering, you must create a lifecycle rule. You can also use the AWS Management Console to enable S3 Intelligent-Tiering. For more information, see Getting Started Using Amazon S3 Intelligent-Tiering in the AWS documentation.

Single Availability Zone

To create a Single Availability Zone file system, choose the Single-AZ option when you create an FSx for Windows File Server file system. Amazon FSx also takes highly durable backups (stored in Amazon S3) of your file system daily using the Windows Volume Shadow Copy Service, and allows you to take additional backups at any point. Keep in mind some of the issues with using a Single Availability Zone. For example, the SMB file share becomes inaccessible if an affected Availability Zone where the file system is provisioned goes down for hours at a time. If you require access to the data, you must restore it from backups in an available Availability Zone within the source Region. For more information, see the Use a single Availability Zone section of this guide.

Backup to URL

For SQL Server 2022, the backup to URL feature allows direct backup to Amazon S3. This is the ideal backup approach for SQL Server 2022 running in AWS as you get the full feature set of Amazon S3 at the storage layer and remove the cost of the AWS Storage Gateway appliance needed in prior versions to facilitate this functionality. There are two primary costs to consider when implementing this feature: data transfer costs and the S3 storage class chosen. If you want the native disaster recovery capabilities of Amazon S3, then you must factor in that cross-Region Replication incurs cross-Region data egress costs. To learn more about how to configure this option, see the Backup SQL Server databases to Amazon S3 post on the Microsoft Workloads on AWS blog.

Additional resources