3729754 - After run sr_register on Secondary site, the replication between Secondary site and DR site is broken

You notice that in an already established 3-tier System Replication scenario, after sr_register command was run on secondary, the previous registered DR site loses contact with secondary. It will no longer be shown in statistics like python script systemReplicationStatus.py or the site mapping in output of command 'hdbnsutil -sr_state'.

Same error may also seen if you have an established replication B->C and you try to directly register site B under site A to have a replication landscape A->B->C.

Following traces could be observed:
In DR server, following trace will be observed in nameserver trace:
[xxxxxxxx]{-x}[-x/-x] xxxx-xx-xx xx:xx:xx.xxxxxxx e sr_nameserver    SystemReplicationWatchDog.cpp(00073) : could not retrieve source site topology;

In Secondary server however, the trace depends on what command has been run:

• Scenario 1:
  Only sr_register is run on secondary:
  Following trace can be observed in Secondary nameserver:
  [xxxxxxxx]{-x}[-x/-x] xxxx-xx-xx xx:xx:xx.xxxxxxx i sr_nameserver    DRRequestHandler.cpp(01175) : drCheckTopology: Not a source site, won't send topology to secondary.
• Scenario 2:
  sr_enable is also run on secondary, after sr_register
  Following trace can be observed in Secondary nameserver:
  [xxxxxxxx]{-x}[-x/-x] xxxx-xx-xx xx:xx:xx.xxxxxxx e sr_dataaccess    DisasterRecoveryPrimaryImpl.cpp(03488) : Reject new replication connection from 10.180.2.102 because no registration information for siteId=3 found. Please check if the host from 10.180.2.102 is intended to be running and is properly unregistered or removed. If this it not the case, please unregister/remove the site/host from the landscape. To properly unregister a system replication secondary site with hdbnsutil please checkout SAP note 1945676. 

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SAP HANA, platform edition 2.0

KBA , HAN-DB-HA , SAP HANA High Availability (System Replication, DR, etc.) , Problem