Optimised duplication to duplicate images between sites works fine under the same master server.
DataDomain is not yet supporting AIR. We had a call logged at my previous company with EMC. Last feedback in Sept last year was:
DD does not support AIR. This functionality is planned for DDOS 5.3, 2H 2012. Supporting this needs a new DD NBU BOOST plugin.
AIR is not yet supported by EMC/Data Domain. Latest version of DD OS 188.8.131.52 has few improvements like replicating MTREE (you don't need to create a folder under /backup to replicate) but still you also cannot replicate LSU via DD which is the alternate of AIR method.
Automated Import Replication (AIR), introduced in NBU 7.1 over a year ago, cannot be compared to something like LSU replication via DD!
AIR provides true disaster recovery by optimzed duplication of a backup image that also has appended to it, the NBU catalog metadata and, is designed to replicate between different NBU domains.
In each NBU domain, there is a commonly named AIR SLP like AIR1. When domain A uses AIR to domain B, the SLP in domain B will automatically import the catalog metadata into domain B's catalog. Domain A can be hit with a disaster but can fall back to Domain B w/no data loss.
We saw this in Japan where over the weekend, the data in Japan was sent via AIR to a site in San Francisco. Just after AIR completed, the tsunami hit. No data loss.
AIR was introduced in NBU 7.1 on March 17th, 2011 - that means OST customers have been waiting over 370+ days for this functionality.
If an appliance form factor is your preference, why not look at the full line of NetBackup appliances that deliver better performance at a lower cost and........................ you won't get behind on the technical advances that reduce risk, lower operational costs and remove complexity from your backup infrastructure?