## 2. Stop the secondary system:
sapcontrol -nr &lt;instance\_number&gt; -function StopSystem HDB
If you are running with HANA 2.0 you will need to copy the system PKI SSFS key and data file from the primary system to the secondary before registering the secondary system. The corresponding files can be found on the primary:
/usr/sap/&lt;SID&gt;/SYS/global/security/rsecssfs/data/SSFS\_&lt;SID&gt;.DAT
/usr/sap/&lt;SID&gt;/SYS/global/security/rsecssfs/key/SSFS\_&lt;SID&gt;.KEY
3. Register the secondary system as follows:
- a. Enable system replication on the secondary system as user &lt;sid&gt; adm with the following command:
```
hdbnsutil -sr_register --name=<secondarySiteName> --replicationMode=[sync|syncmem|async]--operationMode=[delta_datashipping|
```
```
--remoteHost=<primary_host> --remoteInstance=<primary_systemnr> logreplay|logreplay_readaccess]
```
hdbnsutil -sr\_register Call Options
| Option Name          | Value                                                | Description                                                                                                                              |
|----------------------|------------------------------------------------------|------------------------------------------------------------------------------------------------------------------------------------------|
| --name               | <secondarySiteName>                                  | Alias used to represent the secon­ dary system                                                                                            |
| --remoteHost         | <primary_host>                                       | Nameof the primary host that the secondary registers with                                                                                |
| --remoteInstance     | <primary_instancenr>                                 | Instance number of primary                                                                                                               |
| --replicationMode    | [sync|syncmem|async]                                 | Log replication modes                                                                                                                    |
| --operationMode      | [delta_datashipping|logreplay|logre­ play_readaccess] | Log operation mode                                                                                                                       |
| --online             | N/A                                                  | If the system is running you can use this parameter to automatically per­ form a system restart. Not relevant if the system is shut down. |
| --force_full_replica | N/A                                                  | Use this parameter to initiate a full data shipping. Otherwise a delta data shipping is attempted                                        |
To check if the system has been successfully enabled for system replication with hdbnsutil run:
```
cd /usr/sap/<sid>/HDB<instancenr>/exe ./hdbnsutil -sr_state
```
- b. Start the secondary system to reinitialize it with the following command:
As &lt;sid&gt; adm:
```
/usr/sap/hostctrl/exe/sapcontrol -nr <instance_number> -function StartSystem HDB
```
Once the secondary system is started, the replication process will start automatically.
## Related Information
General Prerequisites for Configuring SAP HANA System Replication [page 35]
Create Data Backups and Delta Backups
Rename an SAP HANA System Host
Host Name Resolution for System Replication
Create Data Backups and Delta Backups (SAP HANA Studio)