We're mainly using CephFS using the Centos/Rhel 7 kernel client and I'm pondering if I should go for bluestore compression mode" = passive or aggressive with this client to get compression on (preferably) only compressible objects.

Is there any list of CephFS clients that send compressible hints?

If not, is there any other way to detect this, other than checking a client by just writing some compressible and some uncompressible data?

The documentation is rather sparse on this matter, as far as I can see.