MSSQL Transaction Logs – Disk Space Management

MSSQL transaction logs are a key element of the database system that can quickly fill up disk space if not properly managed. In this article, I will show you how to effectively manage MSSQL transaction logs and prevent disk space issues.

The .ldf file can grow to hundreds of GB if MSSQL transaction logs are not regularly backed up or truncated.

Recovery Models for MSSQL Transaction Logs

FULL Recovery Model

• Retains every transaction until log backup
• Enables point-in-time recovery
• Requires regular log backups

SIMPLE Recovery Model

• Automatically truncates logs after checkpoint
• Recovery only to last full backup
• No log backups required

BULK_LOGGED Recovery Model

• Hybrid approach for bulk operations
• Suitable for ETL processes

More about recovery models in Microsoft SQL Server documentation.

SQL Commands for Managing MSSQL Transaction Logs

View Recovery Models

SELECT name AS Database, recovery_model_desc AS Mode
FROM sys.databases
WHERE name NOT IN ('master', 'model', 'msdb', 'tempdb');

Change Recovery Model and Shrink Log

ALTER DATABASE [dbname] SET RECOVERY SIMPLE
DBCC SHRINKFILE ([logfile], 100)

Backup Transaction Log

BACKUP LOG [database] TO DISK = 'C:\Backups\db_log.trn'

Recommendations for MSSQL Transaction Logs

Environment	Recovery Model
Production systems	FULL + regular log backups
Dev/Test	SIMPLE
Reporting databases	SIMPLE

Summary

Managing MSSQL transaction logs is critical for stability. Key points:

• FULL model requires regular log backups
• SIMPLE model automatically truncates logs
• Improper configuration leads to disk filling

More guides on Azure and databases in our section.