This spare? HDD came from near the IOMs in the ISM shelves in the MCAM cabinet. It is actually a 2.5" PATA HDD mounted in an Adtron adapter to make it a SCSI drive. Despite the HDD itself supposedly being 30GB, the capacity was apparently somehow set to about 9.1GB.
As a result of the size limit, I decided to dump the drive as raw PATA too. This resulted in the 30GB image, which means the adtron itself was doing the size limiting.