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Disaster planning and Unity


We have 2 main locations where over 300 remote sites terminate. We have a centralised callmanager cluster and redundant unity system. My question is how can we plan for a disaster. For callmanager we have a subscriber at a colocation, but what about unity and message store? can we have a redundant unity and message store at a colocation.

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Cisco Employee

Re: Disaster planning and Unity

In general, we don't support Unity failover servers separated via a WAN. On some occasions this has been done, but it depends entirely on the delay and bandwidth characteristics of the link. Essentially it needs to have LAN-like delay and no bandwidth restrictions or packet loss. In other words, if the only connection between the sites as a low-speed frame-relay or something similar, then this would be a bad idea. Callmanager actually has similar requirements.

Since Unity (with failover) uses an off-box messages store, those products have to be evaluated separately. With Exchange (2000/2003), Microsoft does support stretched clusters for this type of environment, but again the bandwidth/delay characteristics are extremely important. You can take a look at this article to get some idea of what's involved:

This would be necessary for unified messaging environments, since our tools (DiRT) only backs up the Inbox folder, not the entire mailbox.

If you decide to go this route, it helps to involve someone from the Cisco account team to help qualify the environment.

On the other end of the spectrum (certainly in terms of cost), what a number of folks do is simply to do DiRT backups of the Unity server to the remote site. Then they would have a pre-built Unity server that does not have any configuration in it yet. In case of a disaster, all that's required is a DiRT restore and you're up and running.

Community Member

Re: Disaster planning and Unity

Thanks for the input. Do you know anyone who has done unity failover accross sites with exchange cluster?? provided they had sufficient bandwidth between the sites? Any feedback would be highly appreciated.

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Community Member

Re: Disaster planning and Unity

Hi Parwal, Did you get any replies for this post as I have exactly the same topology?



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