one weird trick to speed up your zfs metadata by 10x

the trick is adding a “special” vdev 🚄⚡

$ time du -sh /ocean/private
2.5T    /ocean/private
11:16.33 total

(send, add special, recv, remove l2arc, reboot)

$ time du -sh /ocean/private
2.5T    /ocean/private
1:17.16 total

https://forum.level1techs.com/t/zfs-metadata-special-device-z/159954