Verifying the initial installation

The following steps verify the correct setup of the ERS replication.

The commands listed with each verification step assume an ASCS setup. If you verify a Java setup replace the following instance names:

ASCS with SCS
DVEBMGS with J
D with J

The syntax of the ifconfig commands shown in the samples below applies to the AIX operating system.

For Linux, replace the AIX commands with the following Linux commands:

Add IP alias

AIX: ifconfig <interface_name> <IP_alias> netmask <IP_netmask> alias up
Linux: ifconfig <interface_name>:<unique_number> <IP_alias> netmask <IP_netmask> up

Delete IP alias

AIX: ifconfig <interface_name> <IP_alias> delete
Linux: ip addr del <IP_alias> dev <interface_name>

Prerequisites:

All instances are stopped.
Execute all steps as <sid>adm user.

For the verification the SAP system is started and a manual failover of the ASCS and ERS is executed twice. First a failover of the ASCS instance from the first node to the second node and then a failover of the ASCS instance from the second node back to the first node.

Verification step: Initial start - ASCS on first node and ERS on second node:
1. Start the ERS instance on the second node:
```
ifconfig <interface_name> <ERS_IP_alias> netmask <IP_netmask> alias up
startsap r3 ERS<ID>
```
2. Start ASCS and the Primary Application Server instance on the first node:
```
ifconfig <interface_name> <ASCS_IP_alias> netmask <IP_netmask> alias up
startsap r3 ASCS<ID>
startsap r3 DVEBMGS<ID>
```
3. Start the Additional Application Server instance on the second node:
```
startsap r3 D<ID>
```
4. Check the replication status for each ERS instance on the second node by using the ensmon (ENSA) utility or the enq_admin (ENSA2) utility.
```
ensmon pf=/usr/sap/<SID>/ERS<ID>/profile/<SID>_ERS<ID>_<node2>
```
  - To check the replication status by using the ensmon utility, run the following command:
```
ensmon pf=/usr/sap/<SID>/ERS<ID>/profile/<SID>_ERS<ID>_<node2>
```
    Select the task Get replication information. An output that is similar to the following example is displayed:
```
..Replication is enabled in server, replication server is connected. Replication is active... 
```
  - To check the replication status by using the enq_admin utility, run the following command:
```
enq_admin --replication_state pf=/usr/sap/<SID>/SYS/profile/<SID>_ASCS<ID>_<ASCS_HOSTNAME>
```
    An output that is similar to the following example is displayed:
```
Enqueue Server 2 Replication-State = ON 2019-03-19 01:17:09; OK; 'Replication State'; Response=294 usec 
```
5. Verify successful start of all Application Servers:
  - Logon to the Primary Application Server for ABAP using the SAP graphical user interface (SAPGUI).
  - Logon to the Additional Application Server for ABAP using the SAP graphical user interface (SAPGUI).
  - Logon to the Primary Application Server for Java™ using a web browser. The default is:
    http://node1:5<ID>00/index.html
  - Logon to the Additional Application Server for Java using a web browser. The default is:
    http://node2:5<ID>00/index.html
Verification step: Change replication direction - (A)SCS on second node and ERS on first node:
1. Stop Additional Application Server instance on the second node:
```
stopsap r3 ERS<ID>
stopsap r3 D<ID>
ifconfig <interface_name> <ERS_IP_alias> delete
```
2. Stop ASCS, ERS and Primary Application Servers instances on the first node:
```
stopsap r3 DVEBMGS<ID>
stopsap r3 ASCS<ID>
ifconfig <interface_name> <ASCS_IP_alias> delete
```
3. Start ASCS IP instances on the second node:
```
ifconfig <interface_name> <ASCS_IP_alias> netmask <IP_netmask> alias up
startsap r3 ASCS<ID>
```
4. Start ERS instances on the first node:
```
ifconfig <interface_name> <ERS_IP_alias> netmask <IP_netmask> alias up
startsap r3 ERS<ID>
```
5. Check the replication status for each ERS instance on the second node by using the ensmon (ENSA) utility or the enq_admin (ENSA2) utility.
  - To check the replication status by using the ensmon utility, run the following command:
```
ensmon pf=/usr/sap/<SID>/ERS<ID>/profile/<SID>_ERS<ID>_<node2>
```
    Select task Get replication information. An output that is similar to the following example is displayed:
```
..Replication is enabled in server, replication server is connected. Replication is active... 
```
  - To check the replication status by using the enq_admin utility, run the following command:
```
enq_admin --replication_state pf=/usr/sap/<SID>/SYS/profile/<SID>_ASCS<ID>_<ASCS_HOSTNAME>
```
    An output that is similar to the following example is displayed:
```
Enqueue Server 2 Replication-State = ON 2019-03-19 01:17:09; OK; 'Replication State'; Response=294 usec 
```
6. Start the Primary Application Server instance on the first node:
```
startsap r3 DVEBMGS<ID>
```
7. Start the Additional Application Server instance on the second node:
```
startsap r3 D<ID>
```
8. Verify successful start of all Application Servers:
  - Logon to the Primary Application Server for ABAP using the SAP graphical user interface (SAPGUI).
  - Logon to the Additional Application Server for ABAP using the SAP graphical user interface (SAPGUI).
  - Logon to the Primary Application Server for Java using a web browser. The default is:
    http://node1:5<ID>00/index.html
  - Logon to the Additional Application Server for Java using a web browser. The default is:
    http://node2:5<ID>00/index.html
Verification step:Change replication direction: ASCS on first node and ERS on second node:
1. Stop ERS and Primary Application Server instance on the first node:
```
stopsap r3 DVEBMGS<ID>
stopsap r3 ERS<ID>
ifconfig <interface_name> <ERS_IP_alias> delete
```
2. Stop ASCS and Additional Application Servers instances on the second node:
```
stopsap r3 D<ID>
stopsap r3 ASCS<ID> <virtual ASCS host name> 
ifconfig <interface_name> <ASCS_IP_alias> delete
```
3. Start ASCS instances on the first node:
```
ifconfig <interface_name> <ASCS_IP_alias> netmask <IP_netmask> alias up
startsap r3 ASCS<ID>
```
4. Start ERS instances on the second node:
```
ifconfig <interface_name> <ERS_IP_alias> netmask <IP_netmask> alias up
startsap r3 ERS<ID>
```
5. Check the replication status for each ERS instance on the second node by using the ensmon (ENSA) utility or the enq_admin (ENSA2) utility.
  - To check the replication status by using the ensmon utility, run the following command:
```
ensmon pf=/usr/sap/<SID>/ERS<ID>/profile/<SID>_ERS<ID>_<node2>
```
    Select task Get replication information. An output that is similar to the following example is displayed:
```
..Replication is enabled in server, replication server is connected. Replication is active...
```
  - To check the replication status by using the enq_admin utility, run the following command:
```
enq_admin --replication_state pf=/usr/sap/<SID>/SYS/profile/<SID>_ASCS<ID>_<ASCS_HOSTNAME>
```
    An output that is similar to the following example is displayed:
```
Enqueue Server 2 Replication-State = ON 2019-03-19 01:17:09; OK; 'Replication State'; Response=294 usec
```
6. Start Primary Application Server instance on the first node:
```
startsap r3 DVEBMGS<ID>
```
7. Start Additional Application Server instance on the second node:
```
startsap r3 D<ID>
```
8. Verify successful start of all Application Servers:
  - Logon to the Primary Application Server for ABAP using the SAP graphical user interface (SAPGUI).
  - Logon to the Additional Application Server for ABAP using the SAP graphical user interface (SAPGUI).
  - Logon to the Primary Application Server for Java using a web browser. The default is:
    http://node1:5<ID>00/index.html
  - Logon to the Additional Application Server for Java using a web browser. The default is:
    http://node2:5<ID>00/index.html

After successful verification everything has to be stopped. All virtual IP addresses have to be deactivated.