High Availability + Disaster Recovery (
3 Node HADR) has been a hot topic since HA/DR (2 Node) was released for customers back in September 2016. I am exited to announce that it is finally here and available for SAP ASE customers running SAP ASE 16.0 SP03 PL03 and above.
This solution is meant to provide a Disaster Recovery solution on top of High Availability solution. This means, the customers who currenty are running High Availability with SAP ASE on Business Suite (
Synchronous Replication) will be able to add a 3rd node as a Disaster Recovery (
Asynchronous Replication) node.
A 3 node HA+DR solution consists of 2 High Available nodes and a 3rd node that setup in a remote location for disaster recovery scenarios. The HA pair can be managed by Fault Manager to manage any failover between node 1 and node 2.
Key points to note for this scenario:
- No re-setup required for your current HA pair. This means, no downtime required for your High Availabiltiy pair.
- DR Node can be removed from the setup without affecting the current High Availabiltiy setup.
- Replication between Primary and Standby Host should be configured for synchronous replication.
- Failover only possible between Primary and Standby. The 3rd node cannot be used as a primary node (unless you break replication and manually redirect your application to use the 3rd Node.
- Replication to 3rd node (DR Standby) is asynchronous to avoid any performance impact due to high latency between Data Centers.
- Replication path requires the standby Replication Server to be active.
- Primary, Standby and DR Standby must have the same:
- Operating system and its patch levels
- SAP ASE version
- ASE Configuration
- ASE Logins / Passwords
- Character Set
- Sort Order
If you are unfamiliar with the current 2 node solution, check out my
blog from back in 2016. The 2 node HA/DR setup looks as follows:
After we add the 3rd node to the architecture it will look like as follows:
As mentioned above, failover can only happen between the parimary and standby hosts. The setup will look like as follows after failover:
Documentation:
HADR User Guide for SAP ASE SP03 PL03 can be found
here.
Guide to add a DR Node to a currently running High Availbility Setup on SAP ASE 16.0 SP02 PL03
can be found
here.