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New Member

Unity VM Failover 2, 3 or 4 Servers Required?

In order to impliment failover for Cisco Unity I am reading that exchange cannot be hosted on either the primary or failover Unity Server and must be loaded on another server. The question comes up, wouldn't this mean that for actual failover you would need 4 servers, 2 Servers for Unity Failover and 2 servers to run exchange. I would assume that if you use only 3 servers if the exchange server failed Unity would not work. Is this correct? Also is there any particular reason why you can't run exchange on 2 Unity Servers in failover config when you can run exchange and unity on one server non failover?

Cisco Employee

Re: Unity VM Failover 2, 3 or 4 Servers Required?

Both the Unity servers in a failover configuration would connect to the same off-box Exchange sever (for a total of three servers). Those Unity servers share the same system mailbox on Exchange. If Exchange was hosted on one of the Unity servers in a failover configuration, and that particular Unity server went down, the secondary Unity server wouldn't have any Exchange server to connect to.

In the case where the Exchange server goes down, the Unity server (primary or secondary) would go into what we call "Umr mode". That's where Unity will record new messages that come in to the local Unity disk drive. Messages left after the Exchange server goes down would be accessible, but any messages left prior to Exchange going down would be inaccessible until the Exchange server is operational.

New Member

Re: Unity VM Failover 2, 3 or 4 Servers Required?

OK, I have not configured a Failover server before and am doing one now. The sales of the equipment initially thought that the customer was going to do UM but instead has changed their minds and now are only VM. With that I have 2 Unity servers and they are to be setup as failover, but I don't have an off box Server to provide DC and Exchange so am I out of luck for Failover?



Cisco Employee

Re: Unity VM Failover 2, 3 or 4 Servers Required?

In a fail-over configuraiton, neither Unity server can be the Exchange server or hold a message store. Here's a link...

If Exchange was to be placed on one of the Unity servers in the failover configuration, it would be completely non-TAC supported.

However, you might not be out of luck. You can actually use another Exchange server to home those mailusers. If this situation, the voice mail subscribers would actually use additional, separate Exchange mailboxes than the existing Exchange accounts on the system. There would actually be a separate email account for Unity and for email messaging. The VM licensing with Unity covers the CALs for those Exchange "voice mail only" boxes, even if the accounts will be on an Exchange server other than Unity.

Under Unity VM, if for whatever reason, the same Exchange account is used for voice messages and email (there's any client access to those voice messages other than the phone or Unity VMI), those accounts would be under licensing violation against Microsoft and Cisco.

It's a confusing subject.

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