Tiered/cached storage and DragonFlyBSD

[my123 (@never_released)]

Hi,

On my laptop, I use a DragonFlyBSD VM with NFS to use HAMMER2 features. 
(ZFS for example doesn't support on-demand deduplication).

Is there any way to combine a part of my SSD with the comparatively huge 
HDD to make burst writes better (and have them committed to HDD later, 
in times of low loads)? Linux supports this usecase better, but it 
doesn't have a good filesystem for my usecase.

Thanks,