SQL Server "PRIMARY filegroup is full" — Why Does It Fail to Grow?

Diagnosing SQL Server Error 1105 PRIMARY filegroup full, inspecting sys.database_files, fixed MB vs percentage autogrowth, MAXSIZE vs OS disk capacity, and dedicated user filegroups.

Reviewed by:Principal Database Architect & SRE

Tested Versions: SQL Server 2025 (17.0 CU10 KB5125471) & 2022 (16.0 CU14)

Operational Verification & Reliability Metadata

Last Technical Review: 29 Ekim 2026

Tested VersionsSQL Server 2025 (17.0 CU10 KB5125471) & 2022 (16.0 CU14)

Required PrivilegesALTER DATABASE authority on target database

Risk Assessment

HighExhaustion of PRIMARY filegroup halts both user data updates and internal system catalog metadata writes

Expected OutputAllocation recovery via fixed-MB autogrowth or secondary .ndf datafile addition

Rollback Procedure:Expand MAXSIZE boundaries or purge unneeded staging tables

Microsoft Learn: Database Files and Filegroups

First 60 Seconds Emergency Protocol:

The error string is a symptom, not the root cause. Do not restart the server blindly. Run the diagnostic queries below to pinpoint the actual failure mode.

▸Symptoms

plaintext

Could not allocate space for object 'dbo.Siparis' in database 'app'
because the 'PRIMARY' filegroup is full.

▸Resolution Patterns

1Set Fixed-MB Autogrowth:

sql

ALTER DATABASE app MODIFY FILE
  (NAME = app_data, SIZE = 20GB, FILEGROWTH = 512MB, MAXSIZE = 200GB);

1Add Secondary Data File:

sql

ALTER DATABASE app ADD FILE
  (NAME = app_data2, FILENAME = 'D:\Data\app_data2.ndf', SIZE = 10GB, FILEGROWTH = 512MB)
  TO FILEGROUP [PRIMARY];

•Related Error: SQL Server Msg 9002 Transaction Log Full
•Companion Guide (Oracle): Oracle ORA-01653 Tablespace Full
•Engine Hub: SQL Server Production Hub

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