Backing up a Db2 database offline

For a Db2 deployment, the method for the database backup is to use a Single System View (SSV) backup. This strategy helps you back up all database partitions simultaneously, including the catalog partition. SSV backups provide a single time-stamp for all database partitions, making the recovery simpler. The db2 backup command must be run from the node where the Db2 database service is deployed.

Before you begin

For an offline backup, the database is offline and inaccessible to applications during backup, but there are no ongoing transactions that need to be added to the backup.
You must identify the Db2 catalog node and have an SSH connection to the catalog node. For more information, see Preparing to back up or restore Db2.

Note:

The commands in this procedure use the environment variable containing the default database name ${DBNAME}. If you have multiple databases, please update the variable value or commands accordingly.

Procedure

From a bash shell on the catalog node, switch to the database instance owner and create the directory to hold the backup images:
```
su - db2inst1
mkdir /backup_dir/backup_nnn
```
Where backup_dir is the directory that you create to hold backup images and nnn is an incremental value that puts each backup in a separate subdirectory. The backups can be put into any directory on the cluster that is shared by the container nodes and has sufficient space to hold the backups. If you back up into a different directory, alter these commands as necessary.

Temporarily disable the built-in HA:

sudo wvcli system disable -m "Disable HA before Db2 maintenance"

Connect to the database:
```
db2 connect to ${DBNAME}
```
Find all the applications that are connected to Db2:
```
db2 list applications
```
This command returns a list of all currently connected applications. You can either stop all the connections by closing the applications, or you can enter the following command to disconnect all connections:
```
db2 force application all
```
Terminate the database:
```
db2 terminate
```
Stop the database:
```
db2stop force
```
Ensure that the command completes on all nodes.
Ensure that all Db2® interprocess communications are cleaned for the instance:
```
ipclean -a
```
Turn off all communications to the database by setting the value of the DB2COMM variable to null:
```
db2set -null DB2COMM
```
Restart the database in restricted access mode:
```
db2start admin mode restricted access
```

Run the offline backup with the command:

db2 backup db ${DBNAME} on all dbpartitionnums to backup_dir

Where backup_dir is the full path to the directory you created in Step 1.

The offline backup is run and returns a successful result:

Part  Result
----  ------------------------------------------------------------------------
0000  DB20000I  The BACKUP DATABASE command completed successfully.
0001  DB20000I  The BACKUP DATABASE command completed successfully.
0002  DB20000I  The BACKUP DATABASE command completed successfully.

Backup successful. The timestamp for this backup image is : 20190523210916

Halt the restricted access mode:
```
db2stop force
```
Ensure that all Db2 interprocess communications are cleaned for the instance:
```
ipclean -a
```
Reinitialize the Db2 communication manager to accept database connections:
```
db2set DB2COMM=TCPIP,SSL
```
Restart the database for normal operation:
```
db2start
```
Activate the database:
```
db2 activate db ${DBNAME}
```

As the root user, re-enable the built-in HA monitoring:

sudo wvcli system enable -m "Enable HA after Db2 maintenance"

Confirm that the built-in HA monitoring is active:

sudo wvcli system status 
sudo wvcli system devices

Connect to the database:
```
db2 connect to ${DBNAME}
```

Run the following command to copy over the two keystore files from the keystore directory into the backup directory:
```
cp ${KEYSTORELOC}/keystore.p12 ${BACKUPDIR}
cp ${KEYSTORELOC}/keystore.sth ${BACKUPDIR}
```
When you restore from an encrypted backup, you will need these two keystore files (keystore.p12 and keystore.sth).
For more information about advanced command options, see the BACKUP DATABASE command.

What to do next

For instructions on the recommended restore option, see Using the restore script.