Failback procedure if no new backups were taken after failover to the DR site

Procedure

Stop the DR system by running:

apstop

The following confirmation appears.

[root@dr-e1n1 home]# apstop
Successfully deactivated system

Confirm that the system state is Inactive by running:

ap state -d

The expected output:

[root@dr-e1n1 home]# ap state -d
System state is 'Inactive'
Application state is 'Unknown'
Platform management state is 'Inactive'

Unmount the ext_mnt file system on the DR system by running:
```
mmunmount ext_mnt -a
```

Confirm that the ext_mnt file system is unmounted on the DR system by running:

mmlsmount all -L

The following confirmation appears.

[root@dr-e1n1 home]# mmlsmount all -L

File system ext_mnt is not mounted.

File system ips is mounted on 5 nodes:
  9.0.32.17       e1n2
  9.0.32.48       e8n1
  9.0.32.16       e1n1
  9.0.32.18       e1n3
  9.0.32.47       e7n1

File system platform is mounted on 5 nodes:
  9.0.32.18       e1n3
  9.0.32.47       e7n1
  9.0.32.17       e1n2
  9.0.32.48       e8n1
  9.0.32.16       e1n1

Export the GPFS file system that was created on prod and copied to DR system by running:

mmexportfs ext_mnt -o /home/ext_san.config_dr

This is to remove the file system from the OS so that it can be imported again later.

[root@dr-e1n1 home]# mmexportfs ext_mnt -o /home/ext_san.config_dr

mmexportfs: Processing file system ext_mnt ...
mmexportfs: Propagating the cluster configuration data to all
  affected nodes.  This is an asynchronous process.

Start the DR system by running:

apstart

Starting the DR system is to make sure it is ready for the next failover.

[root@dr-e1n1 home]# apstart
Successfully activated platform, appliance activation request sent

Run the following command and watch until the system state is Active.
```
ap state -d
```
The expected output:
```
[root@dr-e1n1 home]# ap state -d
System state is 'Ready'
Application state is 'Ready'
Platform management state is 'Active'
```
With this step, the failback is complete. You can activate replication going from prod to DR and resume production from the production site.