Unity - DR

This post would give a high end idea on how to configure Unity for DR, I would not go into a step-by-step installation and configuration,for these please refer the appropriate cisco documentation...

There are two scenarios to consider, first you have Unity in your environment and need to setup a secondary node configured for DR, second Unity is installed with failover and you need to shift one node to another datacenter to achieve site DR.



Scenario 1

Install Unity in DR datacenter,the IP address on this node would depend on whether you have stretch vlan's in your environement or not,Unity can be connected to a different subnet,Unlike windows clustering Unity does not have the requirement for both the nodes to be in the same subnet/vlan.



http://www.cisco.com/en/US/docs/voice_ip_comm/unity/42/upgrade/guide/ex/ru_090.html#wp1124930


Scenario 2

Failover Redundancy (Hot Standby) - If we have a LAN grade connection between the two sites then all we need to do is move the passive
node to the DR datacenter,

- Break the current failover config
- Move passive node to DR datacenter
- Power-up passive node and change the IP address (make sure DNS is
updated)
- Reconfigure failover
- Reconfigure the ports in Call Manager for node2 (Note: If Unity is
integrated with multiple CCM clusters,the changes need to be done on
all CCM clusters)


http://www.cisco.com/en/US/docs/voice_ip_comm/unity/42/upgrade/guide/ex/ru_090.html#wp1124930


If you have stretch vlan’s between the two Datacenters then the above is not required, just shutdown node 2 -> move to DR datacenter -> connect passive node to the same vlan and power up and that’s it, node2 would work as expected.


Standby Redundancy (Cold Standby) - Manual Intervention is required, the configuration is same, only automatic failover/failback is disabled,

http://www.cisco.com/en/US/docs/voice_ip_comm/unity/5x/requirements/50cusysreq.html#wp575709


The above listed scenarios assume that you have a tested Exchange DR in place. Now lets assume your primary datacenter goes down, Unity would immediately failover to the DR datacenter but manual reconfiguration might be required depending on how your Exchange DR is setup, If you are using Windows Clustering(Exch 2003) or CCR (Exch 2007) and Exchange services on the passive cluster on DR site start normally then ideally no change in Unity config w.r.t to exchange would be required, this is assuming Unity is pointing to the cluster hostname not the hostname of the exchange box.

The Call Manager failover to the passive Unity node should be automatic and no changes should be required on CCM, This would work in both scenarios, CCM hosted on the primary datacenters and atleast one CCM subscriber node on the DR datacenter or CCM hosted on some other datacenter, eg:- In a managed hosting environment CCM mightnot be colocated with Unity and might be homed at your clients datacenter.