For Calendar Server installations that separate functionality across front-end and back-end machines, the hardware platforms must be the same on each end.
More specifically, due to big-endian versus small-endian incompatibility, you can’t use both an x86 platform machine and a SPARC platform machine in the same Calendar Server deployment containing front-end and back-end machines.
Moreover, mixing Solaris x86 and Linux operating systems for front-end and back-end machines has not been tested and is not currently supported.