# Oracle 19c SE2: Relocating PDB Datafiles to a New Disk




Moving datafiles for a Pluggable Database (PDB) in Oracle 19c Standard Edition 2 doesn't require Enterprise Edition features like online file move. This runbook walks through the safe, offline method with minimal downtime — only the target PDB needs to be closed, not the entire CDB.

---

## Overview

- **Database version:** Oracle 19c SE2
- **Scope:** PDB datafiles only (SYSTEM, SYSAUX, and UNDO are not moved)
- **Downtime:** PDB-only outage
- **Method:** Copy files offline, rename in controlfile, reopen PDB

---

## Prerequisites

- OS access as `oracle` user
- SQL*Plus access as `SYSDBA`
- Sufficient space on the destination disk
- A scheduled maintenance window is recommended
- Keep source files until a backup completes

---

## Step 1: Verify Current PDB Datafile Locations

Connect to the CDB and switch into the target PDB to confirm which files need to be moved.

```sql
sqlplus / as sysdba

ALTER SESSION SET CONTAINER = <your_pdb_name>;

SELECT tablespace_name,
       file_name
FROM dba_data_files
WHERE file_name LIKE '/source_disk/%'
ORDER BY tablespace_name;
```

Note all file paths returned — these are the files you'll be relocating.

---

## Step 2: Create the Destination Directory

Create the target directory structure on the new disk and set the correct ownership and permissions.

```bash
mkdir -p /destination_disk/oradata/<CDB_GUID>/datafile

chown -R oracle:oinstall /destination_disk/oradata
chmod -R 775 /destination_disk/oradata
```

Replace `<CDB_GUID>` with the actual GUID directory name from your environment (visible in the source file paths).

---

## Step 3: Close the PDB

The PDB must be closed before copying its datafiles to ensure consistency.

```sql
ALTER PLUGGABLE DATABASE <your_pdb_name> CLOSE IMMEDIATE;
```

Verify the status:

```sql
SHOW PDBS;
```

Expected result: the PDB should show `MOUNTED`.

---

## Step 4: Copy Datafiles to the New Location

Copy each datafile using `cp -p` to preserve timestamps and permissions.

```bash
cp -p /source_disk/oradata/<CDB_GUID>/datafile/<filename>.dbf \
      /destination_disk/oradata/<CDB_GUID>/datafile/
```

Repeat for every datafile identified in Step 1.

After copying, verify the files arrived:

```bash
ls -ltr /destination_disk/oradata/<CDB_GUID>/datafile/
```

---

## Step 5: Switch to the CDB Root

All controlfile operations must be done from the CDB root container.

```sql
ALTER SESSION SET CONTAINER = CDB$ROOT;
```

---

## Step 6: Rename Files in the Controlfile

Generate the rename commands dynamically based on what's currently registered:

```sql
SELECT
    'ALTER DATABASE RENAME FILE ''' || file_name || ''' TO ''' ||
    REPLACE(file_name, '/source_disk/', '/destination_disk/') || ''';'
FROM cdb_data_files
WHERE con_id = (
    SELECT con_id
    FROM v$pdbs
    WHERE name = '<YOUR_PDB_NAME>'
)
AND file_name LIKE '/source_disk/%'
ORDER BY file_name;
```

Run each line of the generated output. Each statement will look like:

```sql
ALTER DATABASE RENAME FILE
    '/source_disk/oradata/<CDB_GUID>/datafile/<filename>.dbf'
TO
    '/destination_disk/oradata/<CDB_GUID>/datafile/<filename>.dbf';
```

Execute all rename statements before proceeding.

---

## Step 7: Open the PDB

```sql
ALTER PLUGGABLE DATABASE <your_pdb_name> OPEN;
```

---

## Step 8: Validate New File Locations

Switch into the PDB and confirm all datafiles now point to the new disk.

```sql
ALTER SESSION SET CONTAINER = <your_pdb_name>;

SELECT tablespace_name,
       file_name
FROM dba_data_files
WHERE file_name LIKE '/destination_disk/%'
ORDER BY tablespace_name;
```

All files should now show paths under `/destination_disk/`.

---

## Step 9: Final Status Check

```sql
SHOW PDBS;
```

Expected result: the PDB should show `READ WRITE`. If it does, the migration was successful.

---

## Step 10: Remove Old Files (After Validation)

> ⚠️ **Do not remove old files until you have confirmed the PDB is open READ WRITE and a backup of the new location has completed.**

If your database uses **Oracle Managed Files (OMF)**, Oracle will automatically remove the old source files once the rename is committed and the PDB is successfully opened — no manual cleanup needed.

If you are **not** using OMF, remove the old files manually after validation:

```bash
rm -f /source_disk/oradata/<CDB_GUID>/datafile/<filename>.dbf
```

---

## Notes

- This method works with Oracle 19c **Standard Edition 2** — no Enterprise Edition license required
- Online datafile move (`ALTER DATABASE MOVE DATAFILE`) requires Enterprise Edition and is not used here
- Only the target PDB is taken offline; the CDB and other PDBs remain available
- SYSTEM, SYSAUX, and UNDO tablespace files are **not** covered by this runbook
- Always perform this during a maintenance window
- Retain source files until a full backup of the new location is confirmed
- If using OMF, old files are cleaned up automatically — no manual `rm` required