Migration Guide

 

 

ORACLE DATABASE 19c

Migration Guide

Step-by-Step: expdp / impdp — Data Pump Method

 

 

Prepared By	Bidhan Mandal
Designation	Oracle Database Administrator (DBA)
Document Date	09 March 2026
Subject	Oracle DB 19c Migration — expdp / impdp Process
Target	Fresh Compute Instance (Oracle 19c not installed)
Document Ref	ORA-MIG-19C-2026-001

 Overview

 

 

This document provides a complete, step-by-step guide for migrating an existing Oracle Database 19c instance to a new compute instance where Oracle Database software is not yet installed. The Oracle Data Pump utility (expdp/impdp) is used as the migration method.

The migration is divided into four phases: (1) Export from the source server, (2) Transfer of dump files, (3) Installation of Oracle 19c on the target server, and (4) Import on the target server. All steps must be followed in sequence.

 

NOTE:  Both source and target databases must use the same character set (AL32UTF8 recommended). Ensure the target server has at least 2x the disk space of your dump files.

 

PHASE 1 — EXPORT FROM SOURCE SERVER (expdp)

 

STEP 1

Create OS Directory and Oracle Directory Object

 

Log in to the source server as the oracle OS user and create the export directory. Then connect to Oracle as SYSDBA and create the directory object.

 

# Create OS directory on source server mkdir -p /backup/export chown oracle:oinstall /backup/export   # Connect to Oracle database as SYSDBA sqlplus / as sysdba

 

-- Create Oracle directory object pointing to OS path CREATE OR REPLACE DIRECTORY EXPORT_DIR AS '/backup/export';   -- Grant read/write permission to system user GRANT READ, WRITE ON DIRECTORY EXPORT_DIR TO system;   -- Verify the directory was created successfully SELECT directory_name, directory_path FROM dba_directories WHERE directory_name = 'EXPORT_DIR';

 

STEP 2

Run the Data Pump Export (expdp)

 

Run the export from the OS command line. Select Option A for a full database export or Option B to export specific schemas only.

 

# OPTION A: Full database export (recommended) expdp system/password@ORCL \   FULL=Y \   DIRECTORY=EXPORT_DIR \   DUMPFILE=fullexport_%U.dmp \   LOGFILE=fullexport.log \   PARALLEL=4 \   COMPRESSION=ALL

 

# OPTION B: Export specific schemas only expdp system/password@ORCL \   SCHEMAS=HR,SALES,FINANCE \   DIRECTORY=EXPORT_DIR \   DUMPFILE=schema_export_%U.dmp \   LOGFILE=schema_export.log \   PARALLEL=4

 

NOTE:  The %U in DUMPFILE creates multiple numbered files (e.g. fullexport_01.dmp, _02.dmp). This allows parallel export and avoids oversized single files.

 

STEP 3

Verify the Export Files

 

# List export files and confirm sizes ls -lh /backup/export/   # Check the log file for errors grep -i "error\|ORA-\|warning" /backup/export/fullexport.log   # Check total size of export directory du -sh /backup/export/

 

WARNING:  Do NOT proceed to Phase 2 if the export log shows any ORA- errors. Fix the issue and re-run the export.

 

PHASE 2 — TRANSFER DUMP FILES TO TARGET SERVER

 

STEP 4

Transfer Dump Files via SCP or rsync

 

Copy the dump files from the source server to the target server using one of the following methods:

 

# OPTION A: SCP — recommended for smaller databases scp /backup/export/*.dmp oracle@TARGET_SERVER_IP:/backup/import/ scp /backup/export/*.log oracle@TARGET_SERVER_IP:/backup/import/   # OPTION B: rsync — better for large files, supports resume rsync -avzh --progress /backup/export/*.dmp \   oracle@TARGET_SERVER_IP:/backup/import/   # OPTION C: NFS mount (if shared storage is available) mount -t nfs SOURCE_SERVER:/backup/export /backup/import   # Verify files on TARGET server after transfer ls -lh /backup/import/

 

NOTE:  For databases larger than 100GB, compress before transfer: gzip /backup/export/*.dmp — then decompress on target: gunzip /backup/import/*.dmp.gz

 

PHASE 3 — INSTALL ORACLE DATABASE 19c ON TARGET SERVER

 

Since Oracle Database is NOT installed on the target compute instance, complete all steps below before attempting any import. Steps 5–10 must be executed on the TARGET server.

 

STEP 5

Prepare OS — Install Required Packages (as root)

 

# RHEL / OEL / CentOS — installs all Oracle prerequisites automatically yum install -y oracle-database-preinstall-19c   # OR manually install required packages yum install -y gcc make binutils libaio libaio-devel \   libstdc++ libstdc++-devel sysstat elfutils-libelf-devel \   unixODBC unixODBC-devel ksh glibc glibc-devel   # Create oracle OS groups groupadd -g 54321 oinstall groupadd -g 54322 dba groupadd -g 54323 oper   # Create oracle OS user useradd -u 54321 -g oinstall -G dba,oper -m oracle echo "oracle:YourSecurePassword" | chpasswd

 

STEP 6

Configure Kernel Parameters (as root)

 

# Append required parameters to /etc/sysctl.conf cat >> /etc/sysctl.conf << EOF fs.aio-max-nr = 1048576 fs.file-max = 6815744 kernel.shmall = 2097152 kernel.shmmax = 4294967295 kernel.shmmni = 4096 kernel.sem = 250 32000 100 128 net.ipv4.ip_local_port_range = 9000 65500 net.core.rmem_default = 262144 net.core.rmem_max = 4194304 net.core.wmem_default = 262144 net.core.wmem_max = 1048586 EOF   # Apply kernel parameters immediately sysctl -p

 

STEP 7

Set Oracle User Limits (as root)

 

# Append limits to /etc/security/limits.conf cat >> /etc/security/limits.conf << EOF oracle   soft   nofile    1024 oracle   hard   nofile    65536 oracle   soft   nproc     2047 oracle   hard   nproc     16384 oracle   soft   stack     10240 oracle   hard   stack     32768 EOF

 

STEP 8

Create Oracle Directory Structure (as root)

 

# Create Oracle installation directories mkdir -p /u01/app/oracle/product/19c/dbhome_1 mkdir -p /u01/app/oraInventory mkdir -p /backup/import   # Set ownership and permissions chown -R oracle:oinstall /u01 chown -R oracle:oinstall /backup/import chmod -R 775 /u01

 

STEP 9

Set Oracle Environment Variables (as oracle user)

 

# Switch to oracle user su - oracle   # Add environment variables to ~/.bash_profile cat >> ~/.bash_profile << EOF export ORACLE_BASE=/u01/app/oracle export ORACLE_HOME=/u01/app/oracle/product/19c/dbhome_1 export ORACLE_SID=ORCL export PATH=$ORACLE_HOME/bin:$PATH export LD_LIBRARY_PATH=$ORACLE_HOME/lib:/lib:/usr/lib export CLASSPATH=$ORACLE_HOME/jlib:$ORACLE_HOME/rdbms/jlib EOF   # Apply variables to current session source ~/.bash_profile   # Verify echo $ORACLE_HOME echo $ORACLE_SID

 

STEP 10

Install Oracle 19c Software (as oracle user)

 

Download LINUX.X64_193000_db_home.zip from Oracle eDelivery or My Oracle Support, then run the silent installer:

 

# Unzip the Oracle installer into ORACLE_HOME cd $ORACLE_HOME unzip /path/to/LINUX.X64_193000_db_home.zip   # Run silent install (Software Only — no database created yet) ./runInstaller -silent \   oracle.install.option=INSTALL_DB_SWONLY \   ORACLE_HOSTNAME=$(hostname) \   UNIX_GROUP_NAME=oinstall \   INVENTORY_LOCATION=/u01/app/oraInventory \   ORACLE_HOME=$ORACLE_HOME \   ORACLE_BASE=$ORACLE_BASE \   oracle.install.db.InstallEdition=EE \   oracle.install.db.OSDBA_GROUP=dba \   oracle.install.db.OSOPER_GROUP=oper \   DECLINE_SECURITY_UPDATES=true

 

STEP 11

Run Root Scripts (as root)

 

# Switch back to root user exit   # Run root scripts in this exact order /u01/app/oraInventory/orainstRoot.sh /u01/app/oracle/product/19c/dbhome_1/root.sh

 

STEP 12

Create New Database Using DBCA (as oracle user)

 

Create a new empty Oracle database on the target server. This database will receive the imported data in Phase 4.

 

# Run DBCA in silent mode to create the database dbca -silent \   -createDatabase \   -templateName General_Purpose.dbc \   -gdbname ORCL \   -sid ORCL \   -characterSet AL32UTF8 \   -sysPassword YourSysPassword \   -systemPassword YourSystemPassword \   -createAsContainerDatabase false \   -databaseType MULTIPURPOSE \   -automaticMemoryManagement false \   -totalMemory 4096 \   -storageType FS \   -datafileDestination /u01/app/oracle/oradata   # Verify database is up and open sqlplus / as sysdba SELECT name, open_mode FROM v$database;

 

NOTE:  Check character set on source before creating target DB: SELECT value FROM nls_database_parameters WHERE parameter='NLS_CHARACTERSET'; — it must match.

 

PHASE 4 — IMPORT ON TARGET SERVER (impdp)

 

STEP 13

Create Import Directory Object

 

# Confirm dump files exist on target server ls -lh /backup/import/   # Connect as SYSDBA and create directory object sqlplus / as sysdba

 

CREATE OR REPLACE DIRECTORY IMPORT_DIR AS '/backup/import'; GRANT READ, WRITE ON DIRECTORY IMPORT_DIR TO system;   -- Verify SELECT directory_name, directory_path FROM dba_directories WHERE directory_name = 'IMPORT_DIR';

 

STEP 14

Run the Data Pump Import (impdp)

 

Run the import from the OS command line on the TARGET server. Choose the matching option used during export in Phase 1.

 

# OPTION A: Full database import impdp system/password@ORCL \   FULL=Y \   DIRECTORY=IMPORT_DIR \   DUMPFILE=fullexport_%U.dmp \   LOGFILE=fullimport.log \   PARALLEL=4

 

# OPTION B: Schema-only import impdp system/password@ORCL \   SCHEMAS=HR,SALES,FINANCE \   DIRECTORY=IMPORT_DIR \   DUMPFILE=schema_export_%U.dmp \   LOGFILE=schema_import.log

 

# OPTION C: Import with tablespace remapping # Use when tablespace names differ between source and target impdp system/password@ORCL \   FULL=Y \   DIRECTORY=IMPORT_DIR \   DUMPFILE=fullexport_%U.dmp \   LOGFILE=fullimport.log \   REMAP_TABLESPACE=OLD_TABLESPACE:NEW_TABLESPACE

 

WARNING:  Monitor the import in real time using: tail -f /backup/import/fullimport.log

 

STEP 15

Verify Import and Recompile Invalid Objects

 

-- Connect as SYSDBA on target sqlplus / as sysdba   -- 1. Check log for errors HOST grep -i 'ORA-' /backup/import/fullimport.log   -- 2. List invalid objects SELECT owner, object_type, object_name, status   FROM dba_objects   WHERE status = 'INVALID'   ORDER BY owner, object_type;   -- 3. Recompile all invalid objects EXEC UTL_RECOMP.RECOMP_SERIAL();   -- 4. Verify tablespaces are ONLINE SELECT tablespace_name, status FROM dba_tablespaces;   -- 5. Check row counts match source SELECT table_name, num_rows FROM dba_tables WHERE owner = 'YOUR_SCHEMA';   -- 6. Gather fresh optimizer statistics EXEC DBMS_STATS.GATHER_DATABASE_STATS(   estimate_percent => DBMS_STATS.AUTO_SAMPLE_SIZE);

 Post-Migration Checklist

  Network & Connectivity

•     Update tnsnames.ora on all application/client servers to point to new DB server IP

•     Update sqlnet.ora if encryption or timeout settings differ on the new server

•     Test listener: lsnrctl status

•     Test connectivity from application server: tnsping ORCL

 Security

•     Reset application user passwords as required by your security policy

•     Verify Oracle profiles, password complexity rules, and account lockout settings

•     Enable Oracle Auditing (AUDIT_TRAIL) if required

•     Validate Transparent Data Encryption (TDE) settings if used on source

 Performance

•     Gather fresh optimizer statistics: DBMS_STATS.GATHER_DATABASE_STATS

•     Review SGA and PGA settings — ensure they match or exceed source configuration

•     Re-apply any custom database parameters from source spfile/pfile

•     Monitor AWR/ADDM reports after first 24 hours of production load

 Application Validation

•     Run full regression test suite against the new database instance

•     Validate all stored procedures, functions, packages, and triggers compile correctly

•     Test all DBMS_SCHEDULER jobs and batch processes

•     Verify application login and all CRUD (Create/Read/Update/Delete) operations

 Backup & Disaster Recovery

•     Configure and test RMAN backup immediately after go-live on the new server

•     Update monitoring and alerting tools with the new server hostname and IP

•     Update all DBA runbooks and documentation with new connection details

•     Confirm archive log mode is enabled: SELECT log_mode FROM v$database;