Hybrid harddisk for separated ZIL

I´ve wrote some articles about the separated ZIL and the usage of flash disks in the last few days. I proposed the usage of FlashSSD to store the separated log. Put perhaps it´s much easier to use hybrid harddisk than i thought: Hybrid harddisk have commands to pin certain blocks into a flash based NVcache. Thus, it should be feasible to create a partition in the size of the NVcache and use it as the seperate ZIL device. To leverage the NVcache, it should be sufficient to pin down the ZIL partition to the NVcache.