Compressed Backups in SQL Server: Pros, Cons, and Use Cases

SQL Server is a relational database management system that offers powerful data management capabilities. One of the most important tasks for database administrators is creating regular data backups and restoring that data in the event of data loss. Backup operations play a critical role in ensuring data integrity and security.

Using Compressed Backups in SQL Server

SQL Server can compress database backups using a built-in compression feature. This feature lets you store and transfer data backups at a smaller size, which can reduce disk space and network bandwidth usage. However, compressed backup operations can increase CPU usage and affect backup times. That’s why it’s important to optimize the performance of compressed backups in SQL Server.

In this article, we’ll take a close look at the factors that affect the performance of compressed backups in SQL Server. This feature is supported starting with SQL Server 2008 Enterprise edition and all versions above it. It offers some performance advantages and disadvantages.

Advantages:

Faster Backup and Restore Processes: The smaller size of compressed backups can speed up backup processes and make transferring backup files over the network more efficient. Restore processes can also be faster, since less data needs to be restored.

Less Storage Space Used: Compressed backups can reduce the storage space needed to store database backups. This means backups take up less disk space and can make managing database backups easier.

Less Data Transfer: Compressed backups require less data to be transferred over the network, which makes backup and restore operations faster and reduces network traffic.

Less Bandwidth Usage: Compressed backups use less bandwidth on the network, which consumes fewer network resources and can improve network performance.

Disadvantages:

CPU Usage: Creating and restoring compressed backups can take time depending on the system’s CPU power. Heavy CPU usage can slow down compression operations and negatively affect system performance.

Variable Compression Ratio: The compression ratio can vary depending on the data. Data with repeating patterns or low entropy can achieve higher compression ratios, while high-entropy data compresses less. As a result, the compression ratio can vary depending on the data and affect the performance of compressed backups.

Data Integration Challenges: Compressed backups can make data integration with other systems more difficult. If another system or application can’t use compressed backups directly, restoring the backups may require a special process or tool.

More Complex Backup and Restore Processes: Creating and restoring compressed backups can be more complex than normal backup and restore processes. It may require special compression and decompression operations, which can complicate managing and maintaining these processes.

Use Cases:

1. Scenarios Where Saving Disk Space Is the Priority: If saving disk space is the primary goal, compressed backups can be used. Especially for large databases, reducing the size of backup files is an important factor, and compressed backups can meet this requirement.

2. Scenarios Where Fast Backup and Restore Processes Are the Priority: If fast backup and restore processes are critical, compressed backups can be used. Especially in scenarios involving large databases or where fast restore processes are needed, compressed backups can offer faster backup and restore processes.

3. Scenarios With Sufficient CPU Power: Compressed backups can be used in scenarios where the system has sufficient CPU power. If the system’s CPU power is limited, the performance of compressed backups can be negatively affected, and alternative backup methods may be preferable.

Conclusion:

In conclusion, compressed backups in SQL Server can offer advantages like saving disk space and faster backup/restore processes, while also having disadvantages like CPU usage and a variable compression ratio. The use of compressed backups should be evaluated with attention to the scenarios being applied and the system requirements.

Using the query below, you can run a backup with the COMPRESS parameter on the AdventureWorks2014 database to take it as a compressed backup:

BACKUP DATABASE [AdventureWorks2014]

TO DISK = N'C:AdventureWorks2014AdventureWorks2014.bak'

WITH NOFORMAT,

NOINIT, 

NAME = N'AdventureWorks2014-Full Database Backup',

SKIP, 

NOREWIND, 

NOUNLOAD, 

COMPRESSION, 

STATS = 10

GO