During the aggregate creation process System Manager 1.1 will not let you mix disk types in the aggregate even though the raid.disktype.enable option is set to off. The disk types were BSAS - 1TB (Internal shelf) and SATA - 1TB (DS4243). It will also complain about spare types as well even though these two disk types are substitutes for each other.
However, creating the aggregate with both disk types and later adding additional disks of both disk types via the CLI worked just fine.
Very true. But with raid.disktype.enable having a default setting of "off" these days with the advent of the FAS20xx series it's a bit confusing to some people why they can't mix internal SATA and external SATA. I'd assume that since they're both a SAS back-end that performance statistics would be the same, same for internal SAS and external SAS as well. If that's the case one would think that would be a behavior that System Manager should allow - especially since having a single 12 disk aggregate with it's own RAID group plus spare is pretty inefficient.