Is it possible to replicate data between Fredhopper indexing servers?

Question

While setting up quite an elaborate Fredhopper infrastructure, after reading the documentation and this question, I come to the conclusion that it's not really possible to have more than one indexing server per cluster, apart from using Fredhopper's cascading deployment model.

What I want to achieve is that we basically have two indexer servers which get updated simultaneously with a Tridion publish action. I can imagine index server 1 replicating data to index server 2, but as far as I can see, this is not supported out of the box without extra replication jobs.

Is doing this kind of replication even possible? If it is, how should this be built?

Answer 1

The documentation seems to indicate that it is possible, however you can only link to one Fredhopper instance from the smarttarget_conf.xml file it is not possible to have your deployer push to multiple index servers (hence the diagram in the documentation is incorrect). This means you must have a 1-1 relationship between Tridion deployers and FH index servers.

Another important consideration in an outscaled scenario is how promotions are created in the Index Server. Promotions are created in the Index Server via the Tridion GUI and SmartTarget webservice (which again can only be connected to a single index server), so in fact it seems like you can only have one Index Server per Publication Target (without some black magic).

I would love to be corrected on this, as I find it hard to believe that there are no customers out there with failover on their index servers, however this seems to be the only logical conclusion.