SyncIQ and failing back

Hi all,

I'm assuming this question has already been answered somewhere. If so, please point me in the right direction .

With regard to SyncIQ, when failing back to the primary cluster, will this perform a full sync, rather than just changes that occurred whilst in DR? After reading the documentation and looking at a few websites, this seems to be what I am reading but I do not have a definitive answer (such as this doc http://www.ndm.net/isilon/pdf/best-practices-for-data-replication-with-emc-isilon-synciq.pdf).

If that is the case, then that's a real issue when you are talking about 100TB+ of data. It is lucky we have a 40Gb link between Prod and DR datacentres but I imagine others do not have that luxury. Also, what happens to the data already on the Primary cluster?

Any help is appreciated.

Cheers,

Luke.