First, let us understand the replication modes in SAP HANA. Then, we can look at how to check which operation mode is currently configured in your SAP HANA database.
delta_datashipping
The main system sends updates to the backup system little by little, and also sends a bigger update every few minutes. But the backup system does not fully apply everything straight away. So if the main system fails, the backup still needs some time to catch up before it can take over.
logreplay
The backup system first gets a full copy of the main system. After that, it keeps receiving updates and applies them immediately. So if the main system fails, the backup is already almost ready and can take over faster.
logreplay_readaccess
This is similar to logreplay, but the backup system can also be used to read data while waiting as backup. So it is not just sitting idle.
There are a few ways to check the operation mode, so you can use whichever method is most convenient for you.
Using command hdbnsutil
Log in to the operating system as sidadm, then run the command hdbnsutil -sr_state.
hdbnsutil -sr_state
System Replication State
~~~~~~~~
online: true
mode: primary
operation mode: primary
site id: 1
site name: ABC
is source system: true
is secondary/consumer system: false
has secondaries/consumers attached: true
is a takeover active: false
is primary suspended: false
Host Mappings:
saphanadb1 -> [XYZ] saphanadb2
saphanadb1 -> [ABC] saphanadb1
Site Mappings:
ABC (primary/primary)
|---XYZ (async/logreplay)
Tier of ABC: 1
Tier of XYZ: 2
Replication mode of ABC: primary
Replication mode of XYZ: async
Operation mode of ABC: primary
Operation mode of XYZ: logreplay
Mapping: ABC -> XYZ
Hint based routing site:
done.
Using the SQL query in HANA Studio
Execute the SQL command SELECT * FROM M_SYSTEM_REPLICATION
