At REST encryption via Vormetric

We are interested in encrypting data At-Rest on disk, at the specific bucket level. And we are interested in Vormetric as suggested by Couchbase via:

Of course we’d like to collect and understand performance impacts on this decision. We’d like to understand the trade-off via un-encrypted vs encryped. Does Couchbase, along with their suggestion of Vormetric (Thales), publish metrics on this topic? What services are impacted with At-Rest encryption, just data? Are search and GSI impacted (I doubt it) ? Does Thales provide their software for testing?

I’d answer these questions myself by testing it myself, but unfortunately Thales DOES NOT provide their encryption software in a trial and open scenario (archaic).

Your comments are much appreciated!