ORA-27040: File Create Error - Unable to Create Datafile

ORA-27040: File Create Error, Unable to Create File

Error Overview

Error Text: ORA-27040: file create error, unable to create file

ORA-27040 is raised when Oracle attempts to create a new file (datafile, tempfile, redo log, controlfile) at the OS level and the operation fails. The error is accompanied by a specific OS error code that pinpoints the root cause: missing directory, no space, permission denied, or disk quota exceeded.

Common Causes

Filesystem Space

• Filesystem full (no space left on device)
• Disk quota exceeded for Oracle user
• Inode exhaustion on filesystem
• Tablespace autoextend hit filesystem limit

Permissions

• Oracle user cannot write to target directory
• SELinux blocking file creation
• ACL restricting create permissions
• Read-only filesystem mount

Directory Issues

• Target directory does not exist
• Path component is not a directory
• Symlink target missing
• ASM diskgroup not mounted

Resource Limits

• File size exceeds filesystem maximum (e.g., 2GB on old ext2)
• ulimit fsize too low for Oracle user
• File count exceeds DB_FILES parameter

Diagnostic Steps

Read Full Error Stack

ORA-19504: failed to create file "/path/to/file.dbf"
ORA-27040: file create error, unable to create file
Linux-x86_64 Error: 28: No space left on device
Additional information: 1

The OS error and “Additional information” pinpoint the issue.

Common Linux errno Mappings

errno	Meaning	Cause
13	EACCES	Permission denied
17	EEXIST	File exists (may need different error code)
20	ENOTDIR	Path not a directory
28	ENOSPC	No space on device
30	EROFS	Read-only filesystem
122	EDQUOT	Disk quota exceeded

Check Filesystem Space

# Check space at target location
df -h /u01/app/oracle/oradata/PROD

# Check inodes
df -i /u01/app/oracle/oradata/PROD

# Check quotas
quota -u oracle
repquota -av /u01

Verify Directory and Permissions

# Confirm directory exists
ls -la /u01/app/oracle/oradata/PROD/

# Check write permission for oracle
sudo -u oracle touch /u01/app/oracle/oradata/PROD/test_write
ls -la /u01/app/oracle/oradata/PROD/test_write
sudo -u oracle rm /u01/app/oracle/oradata/PROD/test_write

# Check mount options
mount | grep /u01
# Should NOT show 'ro' (read-only)

Check ulimit

# View Oracle user file size limit
sudo -u oracle bash -c 'ulimit -f'

# Should be 'unlimited' or sufficiently large
# Permanent limits in /etc/security/limits.conf:
oracle soft fsize unlimited
oracle hard fsize unlimited

Resolution Steps

1. Free Filesystem Space

# Identify large files
du -h /u01 | sort -h | tail -20

# Clean old archive logs (after backup)
rman target / <<EOF
DELETE NOPROMPT ARCHIVELOG UNTIL TIME 'SYSDATE-7' BACKED UP 1 TIMES TO DISK;
EOF

# Remove old core dumps and trace files
find $ORACLE_BASE/diag -name "*.trc" -mtime +30 -delete
find $ORACLE_BASE/diag -name "core_*" -mtime +7 -delete

# Or extend filesystem (Linux LVM example)
lvextend -L+50G /dev/vg01/lv01
xfs_growfs /u01

2. Fix Permissions

# Set ownership and permissions
chown oracle:oinstall /u01/app/oracle/oradata/PROD
chmod 750 /u01/app/oracle/oradata/PROD

# Test write
sudo -u oracle touch /u01/app/oracle/oradata/PROD/test_file

3. Create Missing Directory

# Create directory tree as oracle
sudo -u oracle mkdir -p /u01/app/oracle/oradata/PROD

# Or as root with correct ownership
mkdir -p /u01/app/oracle/oradata/PROD
chown -R oracle:oinstall /u01/app/oracle
chmod -R 750 /u01/app/oracle/oradata

4. Mount Filesystem Read-Write

# If filesystem is read-only
mount -o remount,rw /u01

# Verify
mount | grep /u01

5. Fix Quota Issue

# Increase quota for oracle user
edquota -u oracle

# Or temporarily disable quotas on filesystem
quotaoff /u01

# After fix, re-enable
quotaon /u01

6. Move to Different Location

-- If original location has space issues, use alternate
CREATE TABLESPACE new_data
DATAFILE '/u02/oradata/PROD/new_data01.dbf' SIZE 1G
AUTOEXTEND ON NEXT 100M MAXSIZE 10G;

-- Or for resize that fails:
ALTER DATABASE DATAFILE 5 RESIZE 2G;  -- if fails on /u01
ALTER TABLESPACE users
  ADD DATAFILE '/u02/oradata/PROD/users02.dbf' SIZE 1G;

7. Increase ulimit

# Edit /etc/security/limits.conf
oracle soft fsize unlimited
oracle hard fsize unlimited
oracle soft nofile 65536
oracle hard nofile 65536

# Re-login or restart database to pick up

Common Scenarios

Scenario 1: ALTER DATABASE Fails Out of Space

SQL> ALTER DATABASE DATAFILE 5 RESIZE 5G;
ORA-19502: write error on file "/u01/oradata/users01.dbf", block number 524288
ORA-27040: file create error, unable to create file
Linux-x86_64 Error: 28: No space left on device

Fix: Free space or extend filesystem; or add datafile in different location.

Scenario 2: Tempfile Creation Fails

SQL> ALTER TABLESPACE temp ADD TEMPFILE '/u01/oradata/temp02.dbf' SIZE 5G;
ORA-25153: Temporary Tablespace is Empty
ORA-27040: file create error
Linux-x86_64 Error: 13: Permission denied

Fix: chown oracle:oinstall on target directory.

Scenario 3: RMAN Restore Fails

RMAN> RESTORE DATABASE;
ORA-19870: error while restoring backup piece
ORA-27040: file create error
Linux-x86_64 Error: 17: File exists

Fix: Remove pre-existing file or use SET NEWNAME to restore to alternate path.

Sample Output

SQL> CREATE TABLESPACE app_data
  2  DATAFILE '/u01/oradata/PROD/app_data01.dbf' SIZE 10G;
CREATE TABLESPACE app_data
*
ERROR at line 1:
ORA-01119: error in creating database file '/u01/oradata/PROD/app_data01.dbf'
ORA-27040: file create error, unable to create file
Linux-x86_64 Error: 28: No space left on device
Additional information: 1

[oracle@host]$ df -h /u01/oradata/PROD
Filesystem      Size  Used Avail Use% Mounted on
/dev/sda1       100G   99G  500M  100% /u01

[root@host]# lvextend -L+50G /dev/vg01/u01
[root@host]# xfs_growfs /u01

SQL> CREATE TABLESPACE app_data DATAFILE '/u01/oradata/PROD/app_data01.dbf' SIZE 10G;
Tablespace created.

Prevention Strategies

Capacity Monitoring

-- Tablespace usage
SELECT df.tablespace_name,
       ROUND(SUM(df.bytes)/1024/1024/1024, 2) AS total_gb,
       ROUND(SUM(df.bytes - NVL(fs.bytes,0))/1024/1024/1024, 2) AS used_gb,
       ROUND(SUM(df.bytes - NVL(fs.bytes,0))/SUM(df.bytes)*100, 1) AS pct
FROM dba_data_files df,
     (SELECT tablespace_name, SUM(bytes) AS bytes
      FROM dba_free_space GROUP BY tablespace_name) fs
WHERE df.tablespace_name = fs.tablespace_name(+)
GROUP BY df.tablespace_name
ORDER BY pct DESC;

# Filesystem monitoring
#!/bin/bash
THRESHOLD=85
df -h | awk -v t=$THRESHOLD 'NR>1 {gsub(/%/,""); if ($5+0 > t) print}'

Pre-Operation Checks

-- Validate space before file operations
DECLARE
    v_required NUMBER := 10*1024*1024*1024; -- 10GB
    v_free     NUMBER;
BEGIN
    SELECT SUM(bytes) INTO v_free
    FROM dba_free_space
    WHERE tablespace_name = 'USERS';

    IF v_free < v_required THEN
        RAISE_APPLICATION_ERROR(-20001,
            'Insufficient space: ' || v_free || ' < ' || v_required);
    END IF;
END;
/

Reasonable AUTOEXTEND Limits

-- Set MAXSIZE to prevent runaway growth
ALTER TABLESPACE users
  ADD DATAFILE '/u01/oradata/PROD/users02.dbf'
  SIZE 1G AUTOEXTEND ON NEXT 100M MAXSIZE 30G;

File Distribution Strategy

• Spread datafiles across multiple filesystems
• Use ASM for automatic balancing
• Separate redo, data, and FRA on different storage

Related Errors

• ORA-01119: Error in creating database file
• ORA-19502: Write error on file
• ORA-19504: Failed to create file
• ORA-27037: Unable to obtain file status
• ORA-27041: Unable to open file
• ORA-27044: Unable to write the header block of file

Troubleshooting Checklist

• Read full error stack including OS errno
• Check filesystem free space with df -h
• Check inode availability with df -i
• Verify Oracle user can write to target directory
• Confirm directory exists and is mounted RW
• Check ulimit fsize for Oracle user
• Verify quotas not exceeded
• Move to alternate filesystem if local full