SQL Server - backup compression algorithm

The "backup compression algorithm" configuration in SQL Server allows administrators to specify the compression algorithm used for compressing database backups. This feature helps reduce the size of backup files, optimize storage space, and enhance backup and restore performance. SQL Server offers different compression algorithms to choose from, each with its own benefits and considerations. 

Available Algorithms

  • MS_XPRESS: This is the default backup compression algorithm in all editions of SQL Server. It provides a good balance between compression ratio and performance. 
  • Intel QAT: The Intel QuickAssist Technology (QAT) backup compression algorithm is available in SQL Server 2022 (16.x) and later versions. It leverages hardware acceleration capabilities to improve compression speed and efficiency. 
  • ZSTD: The ZSTD compression algorithm is faster and more effective than other algorithms. It is available in SQL Server 2025 (17.x) Preview and later versions, offering improved compression performance. 

Security Risks

  1. Data Confidentiality: Compressed backup files may contain sensitive information. If these files are not encrypted, there is a risk of unauthorized access to the data if the backup files are compromised. 
  2. Data Integrity: It is essential to ensure that the chosen compression algorithm does not compromise data integrity. Data should be accurately compressed and decompressed without introducing errors or corruption. 
  3. Performance Impact: Higher compression levels may impact server performance during backup operations, potentially affecting system responsiveness and availability, especially in high-throughput backup scenarios. 

Recommendation

  • When selecting a compression algorithm for database backups, consider the trade-offs between compression ratio, performance impact, and security. Implement encryption for compressed backup files to protect sensitive data and ensure data confidentiality. 
  • Regularly monitor backup operations and validate backup files to ensure data integrity is maintained throughout the backup process.