To increase the speed of your ZFS pool, you can add a SSD cache for faster access, write- and read speeds.
You have to make 2 partitions, one for cache and another for log.
format ssd into 2 logical partitions, type 48.
For example both partitions, half the size of the SSD.
fdisk /dev/sdf
Show status of the zpool
zpool status
Add partition sdf1 as cache
zpool add rpool cache /dev/sdf1
Add partition sdf2 as log
zpool add rpool log /dev/sdf2
Check your modified pool
zpool status