Do not need backups with Veritas Volume Replicator

I had a discussion with a client the other day, and they said backups were NOT necessary because they were using Veritas Volume Replicator. I'm not familiar with this Veritas product, so I found it difficult to debate their position. But that statement was hard to swallow.

The only thing I can think of is that a backup would give them another level of protection against site failure. Can you give me some more points to make?

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Later,
BEDick