Is this even possible?

[Bloodraghe]

Is it possible to setup a 3tb hdd with raid 0 SSD cashing

[thekeemo]

Wikipedia

A RAID 0 can be created with disks of differing sizes, but the storage space added to the array by each disk is limited to the size of the smallest disk. For example, if a 120 GB disk is striped together with a 320 GB disk, the size of the array will be 240 GB (120 GB × 2).

[Vortex1496]

you can cache the HDD to one SSD. however i think what you want to do is cache the HDD to two SSDs in raid 0 this you cannot do i don't think.

[Columbo]

You have to have two equally sized drives. The gold standard is identical drives. The caching stuff would contain 3 drives of which one would be the SSD.